NSTSE Booklet For Class VIII

Q.P.-2015

Paper Code: UN412(1 - 24)

(Code: 412) Q.P.-2016

Paper Code: UN415(1 - 24)

(Set A - Code: 415) Q.P.-2016

Paper Code: UN418(1 - 24)

(Set B - Code: 418) Q.P.-2016

Paper Code: UN421(1 - 24)

(Set C - Code: 421)

Key & Solutions

Class–II

C L A S S : VIII

Class : VIII

Mathematics

What is the value of (a + b)(a2 + b2)(a – b)(a4 + b4)? (A) a4 – b4 (B) a8 – b8

(C) a16 – b16

(D) a16 + b16

If a, b, c are three non-zero rational numbers, identify the false statement. (A) a + (b + c) ≠ (a ÷ b) ÷ c (B) a ÷ b is a rational number (C) a ÷ (–a) = –1 (D) (a – b) ÷ c ≠

a −b + c c

10 men can cut 15 trees in 2 hours. If 2 men leave the job, how many trees will be cut in 3 hours? (A) 20 trees (B) 18 trees

(C) 24 trees

(D) 15 trees

For what value of x is the given statement FALSE? 3 x2 < (3 x)2

(A) –3

(B) 0

(C)

1 3

(D) 1

Which number can replace the question marks in the equation? ? 162 = ? 128

(A) 12

(B) 14

(C) 144

(D) 196

Space for rough work

Paper Code: UN412

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C L A S S : VIII

Diagonal AC of rhombus ABCD is equal to side BC. Find the measure of ∠ A. C

B

D

(A) 90

o

A

(B) 120

o

(C) 240o

(D) 60o

If (x + y)2 = 100 and (x – y)2 = 16, what is the value of xy? (A) 6

(B) 10

(C) 21

(D) 25

The number n is to be added to the given list. If n is an integer, which of the following could be the median of the new list of seven numbers? 3, 4, 6, 7, 10, 12

(A) 6, 7

(B) 6, 6

1 2

1 (C) 6 , 7 2

(D) 5, 6

A sum of money invested at compound interest amounts to ` 800 in 3 years and to ` 840 in 4 years. Find the rate of interest per annum.

1 (A) 2 % 2

(B) 4%

(C) 5%

2 (D) 6 % 3

Space for rough work

Paper Code: UN412

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C L A S S : VIII

The figure is made up of 5 semicircles. The ratio of the lengths AB : BC : CD : DE is 2 : 3 : 1 : 4. Find the perimeter of the 

22 

shaded region.  Take π =  7  

A

(A) 44 cm

B

C D 28 cm

(B) 88 cm

E

(C) 304 cm

(D) 616 cm

Which of the following cuboids can be formed by the given net?

(A)

(B)

(C)

(D) Space for rough work

Paper Code: UN412

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C L A S S : VIII

Identify the true statement. (A)

7 9 11 < < 9 11 13

(B)

9 11 7 < < 11 13 9

(C)

9 7 11 < < 11 9 13

(D)

7 9 11 < > 9 11 13

What is the largest four-digit number which is a perfect cube? (A) 8000

(B) 9261

(C) 9999

(D) 1000

Find the measure of each angle of a parallelogram, if one of its angles is 30o less than twice the smallest angle. D xo

C 2x – 30o

2x – 30o A

(A) 60 , 100 , 90 , 20 o

o

o

o

(C) 100o, 90o, 90o, 80o

xo B

(B) 80o, 40o, 120o, 90o (D) 70o, 110o, 70o, 110o

There would be 10% loss if a toy is sold at 1080 per piece. At what price should it be sold to earn a profit of 20%? (A) ` 12

(B) ` 1296

(C) ` 1440

(D) ` 10

Which of these is the greatest? (A) 544

(B) 2112

(C) 186

(D) 456

Space for rough work

Paper Code: UN412

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C L A S S : VIII

Which of the following could be a value of x in the given figure? A B 5x

D

(A) 30o

(B) 50o

C

(C) 40o

(D) 10o

An equal amount of water is poured into two empty tanks, P and Q, as shown in the figure.

15 cm

12 cm 10 cm 15 cm Tank P

9 cm 10 cm Tank Q

If Tank P is half-filled with water, what is the height of the water level in Tank Q? (A) 7 cm

(B) 8 cm

(C) 9 cm

(D) 10 cm

Sound travels at approximately 1200 km/hr. A gun is fired. After what time will you hear the sound if you are 3 km away from the gun? (A) 13 seconds

(B) 9 seconds

(C) 10 seconds

(D) 19 seconds Space for rough work

Paper Code: UN412

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C L A S S : VIII

Which of the following is NOT a linear equation? (A) 3x – 1 = –2x

(B)

3 x− y=2 4

(C) pq – 3 = p

(D)

x−5 2− x = 2 3

If the angles of a triangle are in the ratio 2 : 3 : 4, what is the difference between the greatest and the smallest angles ? (A) 10°

(B) 20°

(C) 30°

(D) 40°

The cube shown in the figure has edges of length 2, and A and B are midpoints of two of the edges. What is the length of AB? B

A

(A)

2

(B)

3

(C)

5

(D) 6

If a2bc3 = 53 and ab2 = 56, find abc. (A) 5

(B) 52

(C) 53

(D) 54.5

A cooker which is generally sold for 800 was sold for 700 due to festival season. What percent of discount was allowed?

1 (A) 12 % 2

(B) 10%

(C) 14

2 % 7

(D) 15%

What are the factors of 4(a – b)2 – 9(b – c)2? (A) (2a + b – 3c) (2a + 5b – 3c) (B) (2a + b – 3c) (2a – 5b + 3c) (C) (2a – b – 3c) (2a + 5b – 3c) (D) (2a – b –3c) (2a – 5b + 3c) Paper Code: UN412

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C L A S S : VIII

Class : VIII

Physics

Ultrasounds cannot be heard by the human ear because (A) the sounds are too deep. (B) the pitch of the sounds are too high. (C) such sounds are too faint. (D) these sounds are produced by animals like bats. Which of the given shapes will move the fastest through water?

(A)

(B)

(C)

(D)

Why does a series of fast moving still pictures can create an illusion of movement in our eyes? (A) The eye can focus on very rapidly changing pictures. (B) The eye is quicker than the brain. (C) The eye can separate two images only when the interval of separation between them is one-sixteenth of a second. (D) The optical cortex can see through the rapidly moving images. Which point charges will attract each other? 1

2

3

+1C

–1C

+2C

(A) 1 and 2 only

(B) 1 and 3 only

(C) 1 and 2, 2 and 3 only

(D) 1 and 3, 2 and 3 only

Paper Code: UN412

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C L A S S : VIII

The graph given below shows the extension of four different springs P, Q, R and S when loads of different weights were added to the pan attached to the spring individually. P

Extension (cm)

10 8 6 4 2

Q R

0

100

200

300

S

400 500 Load (g)

According to the graph, which spring is the strongest ? (A) P (B) R (C) S (D) Q For a normal eye, in an adult, what is the least distance of distinct vision ? (A) 5 to 8 cm (B) 10 to 15 cm (C) 20 to 25 cm (D) 30 to 35 cm Four marbles were released separately from the top of same inclined plane on different surfaces. On which of the following surfaces does the marble travel a longer distance? (A) Sand paper (B) Mirror (C) Wooden piece

(D) Plastic sheet

What will be the observations at the anode after passing current for sometime in the set up shown below?

(A) Gas bubbles are produced (B) Mass of electrode increases (C) Brown deposit is formed (D) Mass of electrode decreases Paper Code: UN412

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C L A S S : VIII

A syringe is filled with X. When the plunger is pushed inwards, the volume of X remains unchanged.

What can X be ? (A) Helium (C) Nitrogen

(B) Mercury (D) Carbon dioxide

Meteors falling through the earth’s atmosphere give out light. This is due to (A) solar heat absorbed by the meteors. (B) burning gases from the meteors. (C) friction with the air. (D) gravity of the earth. The diagram shows the path of a light ray X, directed at a plane mirror. P O X

M

N

Identify the correct reflected ray. (A) P (B) N (C) O

(D) M

Which comparison between protons and electrons is incorrect?

Protons

Electrons

(A) Located in the nucleus Located outside the nucleus (B)

Negatively charged

Positively charged

(C)

Stationary

Orbit the nucleus

(D)

Heavy particle

Light particle

Paper Code: UN412

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C L A S S : VIII

Identify the hottest star. (A) Yellow star

(B) Blue star

(C) White star (D) Red star Solid potassium iodide does not conduct electricity but molten potassium iodide conducts. Which statement is true ? (A) Potassium iodide has a high melting point. (B) Potassium iodide is not an ionic compound. (C) The ions of potassium iodide are held in a lattice in the solid state but are free to move in the molten state. (D) The ions are not arranged in an orderly manner in the solid state but are arranged in an orderly manner in the molten state. Different volumes of water were poured into four similar glass bottles as shown below.

A girl blew air across the mouth of each bottle and different sounds were produced. Which is the correct sequence of increasing loudness? (B) Q → S → R → P (A) R → P → Q → S (C) S → Q → P → R

(D) P → Q → S → R

What happens when two copper plates are used as electrodes in the voltaic cell ? (A) No electric current will be produced. (B) More electric current will be produced. (C) Lesser electric current will be produced. (D) Copper will be deposited on both the electrodes. Paper Code: UN412

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C L A S S : VIII

Which is NOT the effect of a force ? (A) A car moves slower when you hit the brake. (B) Your hands become warm when you rub them against each other. (C) You can make a call to a friend from your handphone. (D) A glass breaks when it falls from a certain height and hits the floor. Identify the unit of pitch. (A) Hertz (B) Decibels (C) Bar (D) Pleura An object placed 4 m from a plane mirror is shifted by 0.5 m away from the mirror. What is the distance between the object and its image ? (A) 3.5 m (B) 4 m (C) 5 m (D) 9 m A negatively charged rod is moved near a conducting sphere.

Nega vely charged rod

Conduc ng sphere

What will be the movement of the protons in the conducting sphere? (A) Move to right (B) Move to left (C) Moves up (D) Does not move The given diagram shows an experimental set-up.

In which solution will the bulb glow the brightest when the circuit is connected? (A) Ammonium hydroxide (B) Sodium chloride (C) Alcohol (D) Ethanoic acid Paper Code: UN412

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C L A S S : VIII

A student wanted to test the roughness of different surfaces. He dragged an object which was connected to a spring balance over different surfaces at an angle to find out the force required to move the object over each surface. He recorded the results on the graph shown below. Force needed

1

2

3

4

Surface

Which is the roughest surface ? (A) 4

(B) 1

(C) 3

(D) 2

The loudness of a note on a guitar can be increased by increasing the (A) tension on the guitar string. (B) amplitude of vibration of the guitar string. (C) thickness of the guitar string. (D) length of the guitar string. Which object does not use high pressure to perform its normal function ? (A) Knife (C) Hole punch

(B) Thumb tack (D) Hammer

Lightning is seen flashing from the sky to the ground. What is expected to flow down from the sky ? (A) Protons

(B) Electrons

(C) Neutrons

(D) Air molecules Paper Code: UN412

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C L A S S : VIII

Chemistry

Class : VIII

The given bar chart shows levels of air pollutants in various cities. Pollutants (parts per million)

I

II

III

IV

V

Ci es

In which cities, it is advisable for the people to either stay indoors or wear masks when they go outside ? (A) Only I and II

(B) Only I and IV

(C) Only II and V

(D) Only III and IV

In which layer is petroleum found from the given figure?

(A) P

(B) S

(C) Q

(D) R

Which metals are correctly arranged in descending order in the reactivity series of metals ? (A) Lead, zinc, sodium

(B) Lead, sodium, zinc

(C) Zinc, lead, sodium

(D) Sodium, zinc, lead

Paper Code: UN412

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C L A S S : VIII

Four materials, P, Q, R and S, are soaked in a pail of water. The mass of the materials before and after soaking are measured and recorded in the table given below. Which material is the best for making a swim suit ? Material

Mass of material before soaking in water (g)

Mass of material after soaking water (g)

(A)

P

20

40

(B)

Q

50

55

(C)

R

60

90

(D)

S

100

200

Which is the most likely source for the acid rain? (A) Burning of coal

(B) Use of CFC products

(C) Burning of paper (D) Use of bio-degradable products A rusty steel object has to be cleaned before painting. Which substance is a good cleaning agents to remove the rust on the steel object? (A) Water (B) Lemon juice (C) Concentrated sulphuric acid (D) Aqueous sodium hydroxide Which source of energy contributes to air pollution ? (A) Biogas plant

(B) Windmill

(C) Tides on the sea

(D) Hydroelectric power

Paper Code: UN412

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C L A S S : VIII

Carbon monoxide is produced when fuel is burnt with insufficient amount of oxygen. In excessive amount, why could this become harmful to humans? (A) It blocks the transmission of signals in the nervous system. (B) It causes irritation in the respiratory system. (C) It damages the kidney and prevents secretion of waste from the body. (D) It binds with haemoglobin and disturbs the circulation of oxygen in the body. The diagrams given below show what happens to plastic wastes in three different cities. P, Q and R respectively.

Which statement is true ? (A) City R recycles most of its plastic waste. (B) City P recycles a greater percentage of plastic waste than City R. (C) City R burns a greater percentage of its plastic waste than City Q. (D) The city which recycles the greatest percentage of plastic waste is Q. Space for rough work

Paper Code: UN412

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C L A S S : VIII

Which is not the correct use of plastic? Plastic

Use

(A)

PVC

Rain coats

(B)

Polypropene

Microwave ovenware

(C)

Polythene

Buckets

(D)

Polystyrene

Thermocol boxes

It is very dangerous to leave a non-luminous flame burning because (A) the flame is difficult to see and someone may accidentally get burnt. (B) the flame emits poisonous gases. (C) a ‘strike-back’ is highly likely to occur with this type of flame. (D) the flame is steady and will not flicker. What is P in the given equation? P + Oxygen

Carbon dioxide + Water vapour

(A) Magnesium

(B) Water

(C) Kerosene

(D) Camphor

Melamine cannot be remoulded because it (A) has a high melting point. (B) has cross links between the monomers. (C) is a good heat insulator. (D) is not oxidised in the air. Space for rough work

Paper Code: UN412

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C L A S S : VIII

An excess of iron filings are added to a solution containing a mixture of ions Mg2+, Ca2+, Cu2+ and Ag+ respectively. Which two metals will be displaced from this solution? (A) Calcium and copper (B) Calcium and magnesium (C) Copper and silver (D) Magnesium and silver Which activities are not the causes of pollution ? (i) (ii)

Burying biodegradable rubbish in the ground. Burning of trees in the forests to clear land for the cultivation of crops. (iii) Using treated waste from sewage plants to fertilise roadside trees. (iv) Turning waste water into drinkable water.

(A) Only (i) and (ii) (C) Only (i), (ii) and (iv)

(B) Only (ii) and (iii) (D) Only (i), (iii) and (iv)

What does not occur in the reaction between sodium with water?

(A) (B) (C) (D)

It floats on the surface of the water The blue litmus paper turns red It moves rapidly with a hissing sound It burns with a golden yellow flame Space for rough work

Paper Code: UN412

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C L A S S : VIII

Acid rain is a major problem, especially in highly industrialised areas. However, rain water is in fact slightly acidic even without the pollution itself. What is the non-pollutant chemical that causes this acidic property of rain water? (A) Hydrochloric acid

(B) Nitrate

(C) Oxygen

(D) Carbon dioxide

Identify a use of nylon. (A) Carpets

(B) Wrapping film

(C) Disposable foam cups (D) Floor tiles Why is carbon dioxide used in fire extinguishers to put out fire ? (A) It is an inert gas (B) It is an odourless gas (C) It is a highly flammable gas (D) It does not support combustion Which property of diamond is untrue? (A) It is a non-metal. (B) It is a good conductor of heat and electricity. (C) It is hard. (D) It is not ductile. Space for rough work

Paper Code: UN412

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C L A S S : VIII

Class : VIII

Biology

Which micro-organism is matched correctly to its disease respectively? (A) Worms cause sexually transmitted diseases (B) Bacteria cause tuberculosis (C) Protozoa cause ringworm (D) Fungi causes malaria Identify plant cells.

(A) (i) and (iii) only (C) (ii) and (iv) only

(B) (i) and (iv) only (D) (i), (ii) and (iv) only

The diagram shows some plant parts under a microscope.

Which of the following pass(es) through opening X? (A) Sunlight (B) Mineral salts (C) Air (D) Food Country X has a rule that requires anyone who chops down a tree to replant a new tree within the same area. Why do you think there is such a rule? (A) To prevent noise pollution. (B) To prevent land pollution. (C) To conserve natural resources. (D) To ensure that there will be more than 40% of oxygen in the atmosphere. Paper Code: UN412

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C L A S S : VIII

A farmer mixes fertiliser with water and uses it for his crops. Why does he mix the fertiliser with water? (A) To enable the roots to easily absorb it. (B) To enable the leaves to easily absorb it. (C) To enable the plant to carry out photosynthesis. (D) To enable the stem to easily absorb it. Which of the following methods can help improve the quantity and quality of food production? (i) (ii) (iii) (iv)

Increase the price of raw materials Applying modern technology Carrying out research and development Encouraging deforesta on and clearing of wetlands for planta ons

(A) (i) and (ii)

(B) (i) and (iv)

(C) (ii) and (iii)

(D) (iii) and (iv)

All micro-organisms are (A) unicellular organisms. (B) multicellular organisms. (C) organisms that can carry out photosynthesis. (D) organisms that cannot be seen with the naked eye. Which of the following does not take place during pregnancy? (A) Implantation (B) Development of the placenta (C) Production of hormones (D) Menstruation Paper Code: UN412

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C L A S S : VIII

The diagram below shows the root cell of a green plant.

What is the function of part N? (A) It controls activities in the cell. (B) It gives the cell a green colour. (C) It gives the cell a fixed shape. (D) It controls the substances entering and leaving the cell. The table below is a description of two animals. A and B Descrip on Lays eggs Stages in life cycle Take care of their youngone

Animal A Yes 4 No

Animal B Yes 3 Yes

Identify Animals A and B. (A) (B) (C) (D)

Animal A Mosquito Butterfly Butterfly Cockroach

Animal B Frog Pigeon Cockroach Grasshopper

Which diagram shows the sex chromosomes when a sperm fertilises an egg to produce a baby girl? (A)

X

+

X

XX

(B)

X

+

Y

XY

(C)

Y

+

X

XY

(D)

Y

+

Y

YY

Paper Code: UN412

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C L A S S : VIII

Microorganism X releases gas Y that makes bread dough rise. What is microorganism X and gas Y? (A) (B) (C) (D)

X Yeast Bacteria Yeast Mucor

Y Carbon dioxide Carbon monoxide Oxygen Carbon dioxide

Which of the following is a FALSE statement about the organism given below?

(A) It is a parasite. (B) It can conduct photosynthesis. (C) The long whip-like flagellum is used for swimming. (D) It reproduces by splitting. Identify the organism from the given information. I am microscopic. I can cause diseases in plants as well as in animals. I can reproduce only inside another living cell.

(A) A virus

(B) A fungus (C) A bacteria (D) A worm

Which of these cells undergo meiosis to produce haploid cells? (A) Liver cells (B) Lung cells (C) Gonad germ cells (D) Kidney cells Which of the following makes the sperm the decisive factor? (A) A long tail is found only in the sperm which is not present in the egg. (B) There are more number of chromosomes in sperms compared to eggs. (C) Hormones are secreted only in the males which are present in the sperm. (D) A sperm can have either of the two sex chromosomes, while the egg has only one. Paper Code: UN412

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C L A S S : VIII

Usually, when a woman reaches the age of 45 to 50 years, the menstrual cycle stops - this is known as menopause. It is not possible for a woman to become pregnant by natural means once she has attained menopause. Which of the following explains the CORRECT reason for this? (A) The uterus collapses and cannot carry a baby. (B) The eggs no longer allow the sperm to fuse with them. (C) No more eggs are released from the reproductive organs. (D) The bones become porous and cannot support a pregnancy. Which of the following is a micro-organism? (A)

(B)

(C)

(D)

Which one of the following structures found in the given cell indicates that it is a plant cell?

(A) Nucleus (C) Cell membrane

(B) Cytoplasm (D) Cell wall

Ecologically fungi are important because (A) (B) (C) (D)

They act as decomposers and aid in nutrient cycling. They are a major cause of plant diseases. They are parasites. They are producers. Paper Code: UN412

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C L A S S : VIII

Class : VIII

General Awareness

DRDL stands for (A) Defence Research and Development Laboratory (B) Department of Research and Development Laboratory (C) Differential Research and Documentation Library (D) Documentation Research and Development Library Durand cup is associated with the game of (A) Cricket (B) Foot ball (C) Hockey (D) Volley ball Head quarters of UNO are situated at (A) New York (B) Haque (C) Geneva (D) Paris Fathometer is used to measure (A) Earthquake (B) Rainfall (C) Ocean depth (D) Sound intensity Who has been selected for the Mathrubhomi Literary Award? (A) Sugathakumari (B) R.K. Narayanan (C) K. Satchitanandan (D) M. Leelavathi The Ganga Action Plan was originally started in which among the following years? (A) 1982 (B) 1985 (C) 1989 (D) 1993 Entomology is the science that studies (A) Behaviour of human beings (B) Insects (C) The origin and history of technical terms (D) The formation of rocks For which of the following disciplines is Nobel Prize awarded? (A) Physics and Chemistry (B) Physiology or Medicine (C) Literature, peace and Economics (D) All of the above Whose birth anniversary is observed as Rashtriya Ekta Diwas? (A) Bala Gangadhar Tilak (B) Sardar Vallabhai Patel (C) Mahatma Gandhi (D) Lala Lajpat Rai Fire temple is the place of worship of which of the following religion? (A) Taoism (B) Judaism (C) Zoroastrianism (D) Shintoism Paper Code: UN412

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C L A S S : VIII

Class : VIII 1.

Mathematics

Which of the following values are equal ? "



I. 1 II. 4 "  III. 0 IV. 4

(A) I and II (C) I and III

(B) II and III (D) I and IV

2.

A book is marked at 880 and sold for the discount percentage ? (A) 20% (B) 25% (C) 12.5% (D) 15%

770, what is

3.

If n ≠ 0, which of the following must be greater than n ? III. 2 - n I. 2n II. n2 (A) I only (B) I and II only (C) II and III only (D) Neither

4.

What is the percentage change in the area of a rectangle obtained by decreasing its length and increasing its breadth by 5% ? (A) 2.5% increase (B) 0.25% increase (C) 0.25% decrease (D) 2.5% decrease Space for rough w ork

Paper Code: UN 415

1

C L A S S : VIII

5.

If the cost of “N” metres of wire is “d” rupees, what is the cost of “y” metres of wire at the same rate ? (A)

⎛ O@ ⎞ ⎜ N ⎟ ⎝ ⎠

(B)

(Ny)

(C)

(yd)

(D)

⎛ Ny ⎞ ⎜ ⎟ ⎝ d ⎠

6.

The sum of two rational numbers is –3. If one of them is −11 , find the other. 5 4 8 −4 −8 (B) (C) (D) (A) # # # #

7.

The figure given is made up of a square and two isosceles triangles.

m

What is the measure of the angle marked ‘m’ ? (A) 105o (B) 95o (C) 135o (D) &5o Space fo r rou gh w ork

Paper Code: UN 415

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C L A S S : VIII

8.

If 72 × K is a perfect cube, find the value of K. (A) 1 (B) 2 (C) 3 (D) 4

9.

The bar chart shows the number of television sets sold by a shop in 5 months. Number of T.V.s Sold

Y 60 40 20 0

Jan

Feb

Mar April May Months

X

What is the sales in May, as a percentage of the total sales in the 5 months ? (A) 25%

1 (B) 33 % 3

(C) 50%

2 (D) 66 % 3 Space fo r rou gh w ork

Paper Code: UN 415

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C L A S S : VIII

10.

How many faces does the given solid have ?

(A) 6 (C) 8

(B) 4 (D) 12

11.

If N2 = 16 and y2 = 4, what is the greatest possible value of (N – y)2 ? (A) 4 (B) –36 (C) –4 (D) 36

12.

In an examination, a student was asked to find

3 th of 14

3 th of it. His 4 answer was 150 more than the correct answer. What was the number given to him ? (A) 290 (B) 280 (C) 240 (D) 180 a certain number. By mistake, he found

Space fo r rou gh w ork

Paper Code: UN 415

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C L A S S : VIII

13.

In what time will 1000 amount to 1331 at 10% p.a. compounded annually ? (A) 4 years (B) 3 years (C) 2 years (D) 1 year

14.

What is the value of (A) 9 (C) 1.176

7.83 × 7.83 − 1.17 × 1.17 ? 6.66 (B) 6.66 (D) –9

15.

What is the height of a cuboid of volume 216 cm3 if its length and breadth measure 8 cm and 6 cm ? (A) 4.5 m (B) 6 m (C) 4.8 m (D) 9 m

16.

Which of the following is a rational number between 1 1 and ? 4 3 8 7 (A) (B) 15 24 (C)

17.

13 48

(D) Both (A) & (C)

If angles P, Q, R and S of the quadrilateral PQRS, taken in order, are in the ratio 3 : 7 : 6 : 4, what is PQRS ? (A) A rhombus (B) A parallelogram (C) A trapezium (D) A kite Space fo r rou gh w ork

Paper Code: UN 415

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C L A S S : VIII

18.

n and p are integers greater than 1, 5n is the square of a number and 75np is the cube of a number. Find the smallest value for n + p. (A) 14 (B) 18 (C) 20 (D) 30

19.

Two sets of 4 consecutive positive integers have exactly one integer in common. The sum of the integers in the set with greater numbers is how much greater than the sum of the integers in the other set ? (A) 4 (B) 7 (C) 8 (D) 12

20.

A solid is of the shape given.

Which is its top view ?

(A)

(B)

(C)

(D) Space for rough w ork

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21.

A gardener wants to plant 17956 trees and arranges them in such a way that there are as many rows as there are trees in a row. What is the number of trees in a row ? (A) 144 (B) 136 (C) 154 (D) 134

22.

Find the value of 230 + 230 + 230 + 230. (B) 830 (C) 232 (A) 8120

(D) 226

23.

Two cylinders of equal volume have their heights in the ratio 2 : 1. What is the ratio of their radii ? (A) 2 : 1 (B) 1 : 2 (D) 1 : 2 (C) 2 : 1

24.

If (3N – 4)(5N + 7) = 15N2 – aN – 28, what is the value of ‘a’ ? (A) 1 (B) –1 (C) –2 (D) 2

25.

5 women can clear a piece of land in 4 days. How many more women will be required to clear it in one day ? (A) 10 (B) 20 (C) 25 (D) 15 Space fo r rou gh w ork

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Class : VIII

Physics

26.

Identify a surface that produces a diffused reflection. (A) A pane of glass (B) A perfectly reflecting mirror (C) A horizontal wall (D) A concave mirror

27.

Which vibration produces the highest pitch ? (A) 100 vibrations in half a second (B) 150 vibrations in half a second (C) 200 vibrations in one second (D) 250 vibrations in one second

28.

In which of the following activities is friction not useful ? (A) Ice hockey (B) Tug-of-war (C) Rock climbing (D) Swimming

29.

Electric charge can flow through (A) insulators. (B) conductors. (C) both insulators and conductors. (D) neither insulators nor conductors.

30.

Forces are present in all of the following except when (A) a trolley is being pushed. (B) a billiard ball is lying stationary on the table. (C) sunlight is shining on an object. (D) a magnet is sticking to the door of a refrigerator.

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31.

Which of these liquids is an electrolyte ?

(A) 3 only (C) 1 and 3 only

(B) 1 and 2 only (D) 2 and 3 only

32.

Which event does NOT require frictional force ? (A) Rubbing your hands to create heat (B) Cycling (C) Moving a table on the floor (D) Walking from one place to another

33.

The image formed by a plane mirror of an object is (A) virtual, erect, behind the mirror and smaller than the object. (B) virtual, erect, behind the mirror and of the same size as the object. (C) virtual, inverted, behind the mirror and of the same size as the object. (D) real, erect, behind the mirror and of the same size as the object.

34.

Identify a force that can change the direction of a rolling steel ball. (A) Frictional (B) Gravitational (C) Pressure (D) Magnetic

35.

Which electrolyte is used to electroplate an iron nail with copper metal ? (A) Copper oxide (B) Iron sulphate (C) Iron nitrate (D) Copper sulphate

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36.

When sound waves enter the ear, many parts of the ear vibrate. Which part does not vibrate ? (A) Eardrum (B) Ear bones (C) Liquid in the inner ear (D) Nerves leading to the brain

37.

On what factors does the response of the rock to stress depend ? (A) Its temperature (B) The speed of stress applied (C) The confining pressure on the rock (D) All the three

38.

Transferring a charge by touch is called (A) conduction. (B) induction. (C) convection. (D) none of these

39.

What happens when we are exposed to sounds with very high frequencies ? (A) We cannot hear the sounds. (B) The sharp sounds puncture our eardrums. (C) We experience severe pain. (D) We can no longer hear low-frequency sounds.

40.

Identify the energy change that occurs during the process of electrolysis. (A) Chemical energy heat energy chemical energy (B) Heat energy (C) Chemical energy electrical energy (D) Electrical energy chemical energy

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41.

Which statement describes both magnetic force and gravitational force ? (A) The force is both a pulling and a pushing force. (B) The force exists even if there is no physical contact. (C) The unit of the force is joules (J). (D) The force is only able to act on objects made of certain materials.

42.

Two plane mirrors are kept at the following angles one by one. In which case is the number of images formed the maximum ? (B) 60 o (A) 30 o (C) 45 o (D) 90 o

43.

In which situation is friction considered a nuisance ? (A) When a matchstick is struck against the side of a matchbox. (B) When a person in a wheelchair is moving down a ramp with lines etched in its surface. (C) When the gears of a clock have to be oiled to remove squeaking sounds. (D) When a door stopper is used to keep a door open.

44.

Which statement about the Sun is true ? (A) The Sun is a star. (B) The fusion of hydrogen atoms to form helium atoms occurs in the Sun. (C) The Sun has been the source of heat and light as it is now since the Big Bang. (D) All the three.

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45.

Lightning from the cloud strikes the Earth. The lightning will most probably strike (A) a 10-metre tall tree. (B) a 1.5-metre tall man. (C) a 10-metre tall metal flagpole. (D) a pool of water at ground level.

46.

Which statement is not true about the extension of spring balance ?

(A) It measures the amount of gravitational force exerted on the object. (B) The greater the force acting on the spring, the more the spring is extended. (C) Leaving an object hanging from the spring will result in more accurate readings. (D) Readings from this instrument will differ depending on location. 47.

In which of the following is the speed of sound least? (A) Aluminium (B) Sea water (C) Brass (D) Granite

48.

How many dots does the Braille system use ? (A) 5 (B) 6 (C) 10 (D) 11 Paper Code: UN 415

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49.

What happens when electric current is made to flow through a conductor ? (A) Some amount of electrical energy is converted into heat energy. (B) Some amount of electrical energy is converted into mechanical energy. (C) Some amount of mechanical energy is converted into electrical energy. (D) Some amount of heat energy is converted into electrical energy.

50.

Which action is meant to reduce friction ? (A) Dipping hands in chalk before lifting weights in the gym. (B) Placing rollers under a heavy object. (C) Replacing worn-out tyres of a bicycle with new ones. (D) Wearing shoes with rubber soles. Space for rough w ork

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Chemistry

Class : VIII 51.

Fossil fuels are (A) reusable. (C) sutainable.

(B) recyclable. (D) none of these

52.

Ozone depletion is one of the causes which have increased cases of skin cancer. Which statement about the ozone layer is correct ? (A) Holes in the ozone layer allow excessive exposure of harmful radiations. (B) Ozone depletion is caused by the reaction of ozone with CFCs. (C) Ozone layer absorbs radio waves and prevents it from reaching the Earth. (D) Both (A) and (B)

53.

Which characteristic belongs to metals? (A) Malleable and ductile (B) Generally solids at room temperature (C) Form positively charged ions to help conduct electricity (D) All the three

54.

What is the correct definition of a polymer molecule? (A) A macromolecule bound together via hydrogen bonding. (B) A large molecule comprises of one type of atoms joined together. (C) A macromolecule comprises of one or more repeating units. (D) A cluster of small molecules.

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55.

Which statement about the combustion of fossil fuels is not true ? (A) Chemical energy stored in the fuel is converted into other forms of energy. (B) Oxygen is needed for this form of chemical change. (C) Heat energy stored in the carbon compounds of the fossil fuels is released. (D) An example of this combustion reaction is: methane + oxygen → carbon dioxide + water.

56.

A flame produced by burning a substance always points upwards because the (A) gases produced in flame are cold. (B) gases produced in flame are hot. (C) hot gases are lighter and hence rise up. (D) both (B) and (C)

57.

Which key shows an incorrect use of the metal ?

Metal

Use

(A)

Aluminium

Kitchen foil

(B)

Copper

Electrical wires

(C)

Iron

Constructional work

(D)

Mercury

Drink cans

Space fo r rou gh w ork

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58.

Four materials were cut into equal-sized strips. They were then dripped into coloured water from the same height. The height of the water that travelled up the material was measured as shown below.

7 cm

5 cm Strip P

Strip Q

8 cm

6 cm

Strip R

Strip S

Which material should be used to make a beach towel ? (A) R (B) Q (C) P (D) S 59.

A raw material is sustainable if (A) it can be used several times before it is thrown away. (B) it is easy to extract from the ground. (C) it is easy to change into useful substances. (D) there are lots of reserves of this material.

60.

Identify a characteristic of non-luminous flame. (A) No soot is produced (B) Steady flame (C) Blue colour (D) All the three Space fo r rou gh w ork

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61.

The body of a car is made of a steel alloy.

Which of the given properties are suitable for its use in the making of a car ? (A) 1 and 2 only (B) 1 and 3 only (C) 2 and 3 only (D) 1, 2 and 3 62.

Recycling a material involves (A) breaking down the material by burning. (B) dissolving the material to avoid pollution. (C) burying the material so that it is broken down by nature. (D) reprocessing the material so that it can be used again.

63.

When combustion occurs, unburnt carbon particles are produced. These particles are harmful when inhaled by humans as they cause problems related to (A) respiration. (B) digestion. (C) heart. (D) skin.

64.

Which product is not obtained from petroleum ? (A) Petrol (B) Paraffin wax (C) Bees wax (D) Kerosene

65.

Which of these substances has one substance that does not belong to the group because its physical state is different from the other two substances in the list ? (A) Iron, copper, aluminium (B) Oxygen, sulphur, hydrogen (C) Mercury, water, alcohol (D) Carbon, silicon, phosphorus Paper Code: UN 415

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66.

Polyvinylchloride (PVC) is widely used now to replace iron in the making of water pipes. What are the advantages of PVC over iron ? (A) PVC is cheaper. (B) PVC does not rust. (C) PVC is lighter. (D) All the three.

67.

Sleeping in a closed room where coal is burnt is fatal for people because (A) coal is a poisonous substance. (B) poisonous gas, carbon monoxide, is produced due to the incomplete combustion of coal. (C) burning of coal in a closed room evolves carbon dioxide and water vapour, which are harmful. (D) none of the above.

68.

Which form of coal contains the highest carbon content ? (A) Anthracite (B) Peat (C) Lignite (D) Bituminous

69.

Which of these would increase the use of the resources of a particular material ? (A) Reduce the usage of the material (B) Reuse the existing material (C) Recycle the material (D) All of the above

70.

Why zinc can displace copper from copper(II) sulphate ? (A) It is more reactive than copper. (B) It loses electrons during a reaction to form zinc(II) ions. (C) It is lower down the reactivity series compared to copper. (D) It is a strong reducing agent and can reduce copper(II) ions to copper. Paper Code: UN 415

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Class : VIII

Biology

71.

In a biology class the teacher described a cell. She listed the following organelles of the cell – endoplasmic reticulum, mitochondria, nucleus, ribosome, centriole and centrosome. Which cell was she referring to? (A) Prokaryotic cell (B) Plant cell (C) Animal cell (D) Fungi cell

72.

Identify X, Y and Z in the given figure.

Female

Male

Ovary

X

Y

Sperm Z Zygote

(A) (B) (C) (D) 73.

(X) Ovum Testes Ovum Testes

(Y) Testes Ovum Testes Ovum

(Z) Ovulation Implantation Implantation Fertilization

Which of the following crops would enrich the soil with nitrogen ? (A) Apple (B) Pea (C) Paddy (D) Potato Paper Code: UN 415

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74.

What happens when a slice of moist bread left in a dark place for a few days ? (A) Bread dries. (B) Fungal mycelium is developed. (C) Algae develops. (D) It remains the same.

75.

Identify the process taking place in the given figure.

(A) Fission (C) Conjugation

(B) Fertilisation (D) Ovulation

76.

Which organism reproduces in the same way as yeast ? (A) Hydra (B) Amoeba (C) Starfish (D) Flatworm

77.

Which bacteria lives symbiotically in pea plants? (A) Rhizobium (B) Nitrosomonas (C) Azotobacter (D) Clostridium

78.

Which is the longest cell ? (A) Reproductive cell (B) Nerve cell (C) Blood cell (D) Cuboidal cell

79.

Which of these contains smooth muscle ? (A) The Iris of eye (B) Uterus only (C) Bronchi only (D) All of these

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80.

Which of the following cell organelles are respectively called suicidal bags and power houses of the cell ? (A) Mitochondria and lysosomes. (B) Lysosomes and mitochondria. (C) Lysosomes and Golgi complex. (D) Golgi complex and lysosomes.

81.

A student waiting for his results feels nervous and the rate of his heartbeat increases. Which hormone causes this condition ? (A) Insulin (B) Oestrogen (C) Adrenaline (D) Thyroxine

82.

Identify the correct sequence that is followed during the growth of human being ?

1. 3. 5. 7.

Foetus Embryo Adult Child

(A) 2, 3, 1, 4, 7, 6, 5. (C) 3, 2, 1, 4, 6, 7, 5.

2. Zygote 4. Baby 6. Adolescent (B) 2, 1, 3, 4, 7, 5, 6. (D) 1, 3, 2, 4, 7, 6, 5.

83.

Which of the following processes is also called field fallow ? (A) Ploughing (B) Irrigating (C) Sowing (D) Leaving the field uncultivated

84.

Which of the following represents the composition of female destined zygote in human beings ? (A) 22 + X. (B) 44 + XY. (C) 33 + Y. (D) 44 + XX. Paper Code: UN 415

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85.

Which of the following group represents the bacterial disease ? (A) Cholera, tuberculosis, malaria, measles (B) Small pox, tuberculosis, malaria, typhoid (C) Cholera, tuberculosis, typhoid, measles (D) Cholera, anthrax, tuberculosis, typhoid

86.

Bacteriophage is (A) phase in the life cycle of bacteria. (B) bacteria that eats other bacteria. (C) virus that uses bacteria as a host. (D) None of the above

87.

Preparing nursery of plants and then transplanting the saplings is observed in (A) paddy. (B) seasonal vegetables. (C) flowering plants. (D) all of these.

88.

Resources like air, water, soil and sun are (A) artificial and non renewable. (B) natural and renewable. (C) artificial and renewable. (D) natural and non-renewable.

89.

Paleontology is the study of (A) microbes. (B) animals. (C) fossils. (D) planets.

90.

Crop rotation is performed to (A) improve the fertility of soil (B) add more fertilizers (C) Help in weed control and pest control (D) All the above. Paper Code: UN 415

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Class : VIII

General Awareness

91.

Who is the captain of Pro Kabaddi League 2015 winner, U Mumba ? (A) Suresh Pathapalem (B) Anup Kumar (C) Jeeva Kumar (D) Mohammad Ziaur Rahman

92.

The ambitious ‘Beti Bachao Beti Padhao’ campaign was launched from which state ? (A) Haryana (B) Himachal Pradesh (C) Rajasthan (D) West Bengal

93.

A telecom operator named Uninor is recently renamed as Telenor. What is Its new tagline ? (A) Ab life full paisa vasool (B) Life time paisa vasool (C) Ab life with paisa vasool (D) Life ab full of paisa

94.

To make the “Clean India” campaign a mass movement, government has released _______ on October 2, 2015. (A) Swachh Bharat dance form (B) Swachh Bharat anthem (C) Swachh Bharat paintings (D) Swachh Bharat advertisements

95.

Who is the present CEO of Microsoft Corporation ? (A) Steve Ballmer (B) Bill gates (C) Satya Narayana Nadella (D) Sundar Pichai Paper Code: UN 415

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96.

What is the ratio of width of our National flag to its length ? (A) 3 : 5 (B) 2 : 3 (C) 2 : 4 (D) 3 : 4

97.

The recent visit to Ireland by an Indian Prime Minister is approximately after how many years ? (A) 56 years (B) 65 years (C) 60 years (D) 62 years

98.

Identify the given logo.

(A) Angry birds (C) Jet air ways

(B) Twitter (D) Nestle

99.

By defeating whom did Serena Williams won the French Open tennis tournament 2015 ? (A) Victoria Azarenka (B) Lucie Safarova (C) Karolína Pliskova (D) Petra Kvitova

100.

In which language is the song ‘Jana-gana-Mana’ originally composed ? (A) Bengali (B) Hindi (C) Urdu (D) Sanskrit Space fo r rou gh w ork

Paper Code: UN 415

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Class : VIII

Mathematics

1.

If Sudhir will be ‘x’ years old in 3 years, how old was he 5 years ago ? (A) (N + 3) years (B) (N – 8) years (C) (N – 5) years (D) (N – 3) years

2.

Which is greater of 212 and 38 ? (A) 38 (B) 212 (C) Both are equal. (D) Cannot be compared.

3.

Which number is in the middle if

−1 4 6 2 −3 , , , and 6 9 −7 5 4

are arranged in descending order ? (A) 4.

#

(B)

4 9

(C)

− 6

(D)

−$ 7

ABCD is a parallelogram. The angle bisectors of ∠A and ∠D meet at O. What is the measure of ∠AOD ? (B) '0 o (A) "5 o (C) 75 o (D) 180o Space for rough w ork

Paper Code: UN 418

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C L A S S : VIII

5.

Evaluate

3

343 × 125 . 0.064

(A) 875 (C) 807.5

(B) 8.75 (D) 87.5

6.

A shopkeeper fixes the M.P. of an item 35% above its C.P. What is the percentage of discount allowed to gain 8% ? (A) "3% (B) 30% (C) 20% (D) 31%

7.

Which one of the following cubes can be formed by the net given ?

(A)

(B)

(C)

(D)

Space fo r rou gh w ork

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C L A S S : VIII

8.

The area of a trapezium is 28 cm2 and one of its parallel sides is 6 cm. If its altitude is 4 cm, find the length of its other parallel side. (A) " cm (B) 8 cm (C) $ cm (D) 10 cm

9.

One number is 3 times another number. If 15 is added to both the numbers, one of the new numbers becomes twice that of the other new number. Find the numbers. (A) 20 and $0 (B) 25 and 75 (C) 18 and 5" (D) 15 and "5

10.

Find the square root of (A) 0."5 (C) 0.'5

0.081 0.484 2.5 . × × 0.0064 6.25 12.1 (B) 0.75 (D) 0.''

Space fo r rou gh w ork

Paper Code: UN 418

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C L A S S : VIII

11.

The table shows the frequency distribution of grades obtained by 120 students. The data is represented in the following pie chart. , o + !#o

) $o

* #o

Grade

) *  + ,

Frequency

 # "# #

Which sector is labelled incorrectly ? (A) A (B) B (C) C

(D) D Space fo r rou gh w ork

Paper Code: UN 418

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C L A S S : VIII

12.

2 If N +

1 1 = 79, what is the value of N + ? N N2

(A) 7 (C) 13.

(B) ' (D) –'

7'

State which of the numbers given in the box are rational. E

&

EE

%

(A) (i) and (ii) only (C) (ii) and (iv) only 14.

What is the value of ‘x’ if (A) 25

15.

(B) 5

EEE

!

EL

(B) (i) and (iii) only (D) (iii) and (iv) only

aN = a10 and (ay )3 = aN for a > 1 ? ay (C) 20 (D) 15

A rope makes 260 rounds of a cylinder with base radius 20 cm. How many times can it go round a cylinder with base radius 26 cm ? (A) 130 (B) 300 (C) 200 (D) 150 Space fo r rou gh w ork

Paper Code: UN 418

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C L A S S : VIII

16.

Four of the angles of a pentagon are of equal size. The remaining angle is 120o. ,

+

*

 º )

Find the value of each of the equal angles. (A) 210 o (B) 110 o (C) 5"0 o (D) 105 o 17.

If ‘a’, ‘b’, ‘c’ and ‘d’ are consecutive natural numbers and a3 = b3 + c3 + d3, what is the least value of ‘a’ ? (A) $ (B) ' (C) 3 (D) 12 Space fo r rou gh w ork

Paper Code: UN 418

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C L A S S : VIII

18.

2 full after 1.5 l of water was poured 5 in it. The base area of the tank was 250 cm2. What was the height of the tank ? (A) 15 cm (B) 5 cm (C) " cm (D) 8 cm An empty tank was

19.

If x and y are positive integers with x > y and x + xy = 391, what is the value of x + y ? (A) 3'2 (B) 3' (C) 31 (D) "0

20.

The C.I. on a certain sum at 5% for 2 years is 328. Calculate the S.I. for the sum at the same rate and for the same period. (A) 320 (B) 322 (C) 325 (D) 32$

21.

When a certain number ‘m’, is divided by 5 and added to 8, the result is equal to 3m subtracted from 4. Find the value of ‘m’. (A) 2

(B)

" !

(C) −

 !

(D) −

# "

Space fo r rou gh w ork

Paper Code: UN 418

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C L A S S : VIII

22.

Two sides of a rectangle are (3p + 5q) units and (5p – 7q) units. What is its area in sq. units ? (B) 15p2 – "pq + 35q2 (A) 15p2 + "pq – 35q2 (C) 15p2 + 1"pq + 35q2 (D) 15p2 – "pq – 35q2

23.

If two cubes of dimensions 3 cm × 3 cm × 3 cm are placed side by side, what would the dimensions of the resulting cuboid be ? (B) 12 cm × 12 cm × 12 cm (A) $ cm × $ cm × $ cm (C) ' cm × $ cm × 3 cm (D) $ cm × 3 cm × 3 cm

24.

Find the sum of the powers of the prime factors in 108 × 192. (A) 5 (B) 7 (C) 8 (D) 12

25.

If each edge of a cube is increased by 25%, what is the percentage increase in its surface area ? (A) 25% (B) "8.75% (C) 50% (D) 5$.25% Space fo r rou gh w ork

Paper Code: UN 418

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Class : VIII

Physics

26.

If the angle of incidence is 50°, then the angle between the incident ray and the reflected ray is (A) 50°. (B) 100°. (C) 130°. (D) 80°.

27.

What is the audible range of sound that can be detected by the human ear ? (A) 0 to 20 Hz (B) 20 to 20,000 Hz (C) 20,000 to "0,000 Hz (D) none of these

28.

Friction is NOT useful at all between the (A) tyres on cars and the ground. (B) sports shoes and the ground. (C) parts in a machine. (D) brakes and the wheels on cars.

29.

Which natural calamity cannot be predicted accurately in advance ? (A) Flood (B) Cyclone (C) Earthquake (D) Famine

30.

Which statement about the earth and the moon is true ? (A) The moon revolves around the earth because of magnetic force. (B) The force exerted by the moon on the earth is greater than that exerted by the earth on the moon. (C) The force exerted by the moon on the earth causes tides on the earth. (D) The earth exerts a force on the moon, but the moon does not exert any force on the earth. Paper Code: UN 418

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C L A S S : VIII

31.

Electrolytes are able to conduct electricity as they (A) have low melting points. (B) contain freely moving ions. (C) contain ions in fixed positions. (D) contain freely moving electrons.

32.

Identify a force that opposes the motion of a table along the floor. (A) Gravitational (B) Magnetic (C) Frictional (D) Electrostatic

33.

A ball is cut into two halves. On the outer surface of one half of the ball, a shiny aluminium foil is pasted. A candle placed in front of this shiny surface forms an image which is (A) virtual and smaller in size. (B) real and smaller in size. (C) virtual and bigger in size. (D) real and bigger in size.

34.

During a game of basketball, the ball is subjected to only gravitational force when it (Assume that there is no air resistance.) (A) is bounced off the ground. (B) spins while moving through the air. (C) lies stationary on the floor. (D) drops through the hoop.

35.

Solid sodium chloride does not conduct electricity because (A) it is a covalent compound. (B) it has a very high melting point. (C) the sodium ions and the chloride ions are not able to move freely. (D) there are no sodium ions and chloride ions in solid sodium chloride. Paper Code: UN 418

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36.

Sound in a percussion instrument is produced with the help of a (A) string. (B) reed. (C) stretched membrane. (D) wind.

37.

A gold-leaf electroscope is used to detect (A) charge only of a body. (B) and measure charge only of a body. (C) measure and find the nature of charge of a body. (D) none of the above

38.

An object is negatively charged because it contains (A) only electrons. (B) only protons. (C) more electrons than protons. (D) more protons than electrons.

39.

The following are the effects of frictional force except (A) we can walk on a rough horizontal surface easily. (B) machines work inefficiently due to friction between the moving parts. (C) the soles of shoes get worn out with time. (D) plastic placed above our head makes our hair stand.

40.

A voltaic cell consists of (A) two different metals connected by wires and immersed in an electrolyte. (B) two electrodes of the same material connected by wires and immersed in a non-electrolyte. (C) two electrodes of the same material and connected by wires in the external circuit. (D) two different metals and is connected by wires and immersed in two different electrolytes. Paper Code: UN 418

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41.

The following forces could exist without a contact point except (A) frictional force. (B) gravitational force. (C) magnetic force. (D) electrostatic force.

42.

The amount of light reflected depends on the (A) nature of the surface. (B) angle of incidence. (C) angle of reflection. (D) first law of reflection.

43.

Maximum distance a pendulum travels on either side from zero point is called (A) amplitude. (B) time period. (C) frequency. (D) wavelength.

44.

What are stars mainly made up of ? (A) Oxygen and hydrogen (B) Oxygen and nitrogen (C) Hydrogen and helium (D) Water and helium

45.

A comb rubbed with dry hair attracts bits of paper due to (A) electromagnetism. (B) adhesive property. (C) static electricity. (D) current electricity.

46.

Which of these are forces ?

(A) 1, 2 and 3 only (C) 2, 3 and " only

(B) 1, 2 and " only (D) 1, 2, 3 and "

Paper Code: UN 418

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C L A S S : VIII

47.

What is not possible in the given activities ? (A) A man knocks at one end of a long metal pipe and another man hears the knock at the other end. (B) An explosion is heard by an astronaut when a laser beam hits an enemy fighter in space. (C) A whale hears another whale in the deep sea. (D) A mole hears another mole underground.

48.

Plane mirrors are arranged at an angle to get a number of coloured images in a (A) periscope. (B) kaleidoscope. (C) telescope. (D) thermoscope.

49.

What changes take place during electrolysis ? (A) Compounds in molten or aqueous state are broken down into their constituent elements. (B) Electricity is used to break down compounds. (C) Ions of the compounds move to the electrodes to be discharged. (D) All the three

50.

When an airplane flies at a constant speed and height above the ground, which statement is true about the forces acting on the airplane ?

(A) (B) (C) (D)

The thrust is equal to the drag. The lift is equal to the weight. The lift is more than the weight. Both (A) and (B) Paper Code: UN 418

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C L A S S : VIII

Chemistry

Class : VIII 51.

The useful substances obtained from petroleum and natural gas are called (A) petrochemicals. (B) petroleum gas. (C) petrol. (D) natural gas.

52.

Acid rain often causes damage to limestone buildings and monuments as it(s) (A) is soluble in an acid. (B) reacts with the acid. (C) molecule is replaced by the acid molecule in the rain. (D) none of the above.

53.

The reaction of metal X and its compounds are as follows.

Identify metal X. (A) Zn (C) Pb

(B) Mg (D) Cu

54.

Which polymer is manufactured ? (A) Polyethylene (B) Polyvinyl chloride (C) Polysaccharide (D) Both (A) and (B)

55.

A product ‘P’ obtained during the processing of coal to get coke was used for street lighting. It is used now as a source of heat rather than light. Identify ‘P’. (A) Coal gas (B) Coal tar (C) Coal (D) Coke Paper Code: UN 418

14

C L A S S : VIII

56.

Complete combustion of a fuel produces (A) carbon monoxide and nitrogen. (B) carbon dioxide and water vapour. (C) steam and oxygen. (D) hydrogen and carbon dioxide.

57.

Oldsteel drums corrode quickly in a damp atmosphere but aluminium cans do not. Which statement explains the correct behaviour of aluminium ? (A) It has only one valency. (B) It has a lower density than iron. (C) It is above iron in the activity series. (D) It is protected by its oxide layer.

58.

The figure given below shows some of the gear used by rock climbers.

Identify the most suitable properties required in the making of the rope and carabiner.

Rope

Carabiner

(A)

Soft and flexible

Hard and light

(B)

Strong and flexible

Hard and strong

(C)

Hard and waterproof

Light and strong

(D)

Hard and strong

Light and flexible

Paper Code: UN 418

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C L A S S : VIII

59.

Coal tar is a mixture of about 200 substances. The products obtained from it is used as a starting material for manufacturing (A) drugs. (B) photographic materials. (C) explosives. (D) all the three

60.

Global warming leads to a rise in the sea level causing floods. One of the main reason is combustion of fuels that release (A) sulphur dioxide which increases the temperature. (B) carbon monoxide which decreases the temperature. (C) unburnt carbon particles which decreases the temperature. (D) carbon dioxide which increases the temperature.

61.

Which element is always present with iron in steel ? (A) Aluminium (B) Carbon (C) Chromium (D) Nickel

62.

Styrofoam cup is used to serve hot tea or coffee because it is (A) a good conductor of heat. (B) a poor conductor of heat. (C) very flexible in nature. (D) easy to clean. Space fo r rou gh w ork

Paper Code: UN 418

16

C L A S S : VIII

63.

Which type of combustion produces heat, light and sound ? (A) Rapid (B) Explosive (C) Spontaneous (D) All of the above

64.

Different varieties of coal differ in their (A) moisture. (B) volatile nature. (C) carbon content. (D) number of hydrogen atoms.

65.

Which metal is less dense than water ? (A) Calcium (B) Lead (C) Iron (D) Sodium

66.

What is the advantage of recycling jars, bottles and cans that are thrown away everyday ? (A) To reduce landfill rubbish. (B) To save natural resources used to make the objects. (C) To save energy in the manufacture of the objects. (D) All the three

67.

Which fuel has the highest calorific value ? (A) CNG (B) Coal (C) Hydrogen (D) Petrol Space fo r rou gh w ork

Paper Code: UN 418

17

C L A S S : VIII

68.

The source of kerosene is (A) coal tar. (C) crude petroleum.

(B) wood. (D) coal.

69.

PVC is used for making rain coats and seat covers because it (A) can be rolled into thin sheets like polythene. (B) can be coated on a cloth base and is tougher than polythene. (C) has low melting point and is unreactive. (D) has high melting point and is very reactive.

70.

The figure given below shows the structure of a material.

The material shown is (A) bronze. (C) brass.

(B) pewter. (D) duralumin.

Space fo r rou gh w ork

Paper Code: UN 418

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C L A S S : VIII

Class : VIII

Biology

71.

Which set represents the composition of female destined zygote in human beings ? (A) 22 + X. (B) "" + XY. (C) 33 + Y. (D) "" + XX.

72.

Which hormone is secreted by the endocrine gland located on the top of kidneys ? (A) Adrenaline (B) Insulin (C) Progesterone (D) Testosterone

73.

Which of these is/are types of asexual reproduction ? (A) Budding (B) Binary fission (C) Spore formation (D) All the above

74.

Identify pond silk. (A) Spirogyra (C) Chlamydomonas

(B) Volvox (D) Euglena

75.

Which part of the cell is made up of cellulose ? (A) Cell membrane (B) Plasma membrane (C) Cell wall (D) All of these

76.

Identify the wrong statement. (A) Viruses exhibit the characteristic of living as well as nonliving (B) The disease causing microorganisms are called pathogens. (C) Malaria is a bacterial disease caused by Plasmodium (D) Edward Jenner invented the vaccine against small pox Paper Code: UN 418

19

C L A S S : VIII

77.

Choose an aquatic photosynthetic organism. (A)

(B)

(C)

(D)

78.

Through which of these processes your skin replace worn out cells ? (A) Meiosis (B) Mitosis (C) Fragmentation (D) None of these

79.

Which of the following match is correct ?

Disease

80.

Pathogen

(A)

Typhoid

Fungi

(B)

Malaria

Plasmodium

(C)

Sleeping sickness

Bacteria

(D)

Cholera

Virus

Some plants have poorly developed root system and large, flat, wax coated leaves. These plants belongs to which of these categories ? (A) Xerophytes (B) Mesophytes (C) Hydrophytes (D) Epiphytes

Paper Code: UN 418

20

C L A S S : VIII

81.

Identify the process in which a tadpole undergoes number of changes to become an adult frog. (A) Sexual dimorphism (B) Asexual reproduction (C) Polymorphism (D) Metamorphosis

82.

A cell has a defect that results in the loss of its ability to regulate the passage of water, food and wastes into and out of the cell. In which cell structure is this defect most likely to be located ? (A) Ribosomes (B) Chloroplast (C) Cell membrane (D) Endoplasmic reticulum

83.

Match Column-I (type of organism) with Column-II (mode of reproduction)

Column - I

(A) (B) (C) (D)

Column - II

(1) Bacteria

(a) Binary fission

(2) Mucor

(b) Fragmenta on

(3) Yeast

(c) Spore forma on

(4) Spirogyra

(d) Budding

1 - a, 2 - c, 3 - d, " - b 1 - b, 2 - c, 3 - a, " - d 1 - a, 2 - b, 3 - c, " - d 1 - d, 2 - c, 3 - b, " - a

Paper Code: UN 418

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C L A S S : VIII

84.

Which is an iodine - containing hormone ? (A) Insulin (B) Thyroxine (C) Adrenaline (D) Oestrogen

85.

Sandy soil is not good for plants because it (A) cannot hold water. (B) has poor aeration. (C) contain more minerals. (D) has poor drainage.

86.

Fertilisation is external in (A) birds and fish. (C) reptiles and fish.

(B) birds and amphibians. (D) fish and amphibians.

87.

Identify the one that gets its food from host tissue. (A) Nepenthes (B) Cuscuta (C) Drosera (D) Fern

88.

Which set of cell organelles are found only in plant cells ? (A) Cell wall, chloroplast (B) Nucleus, mitochondria (C) Cell wall, mitochondria (D) Cell wall, nucleus

89.

Which of the following is a kharif crop ? (A) Wheat (B) Mustard (C) Rice (D) Gram

90.

Which of the following sequence is in the correct order ? (A) Zygote → Embryo → Foetus → Baby (B) Zygote → Embryo → Baby → Foetus (C) Embryo → Zygote → Baby → Foetus (D) Foetus → Zygote → Embryo → Baby Paper Code: UN 418

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C L A S S : VIII

Class : VIII

General Awareness

91.

What protects earth from the Ultraviolet radiation ? (A) Ozone layer (B) Atmosphere (C) Oxygen (D) Sun

92.

Which of these cities is not the capital of any state in India ? (A) Guwahati (B) Shillong (C) Raipur (D) Ranchi

93.

The given logo belongs to which company ?

(A) Intel (C) Airtel

(B) Volvo (D) Vodafone

94.

Who is the current CEO of Google ? (A) Satya Nadella (B) Mark Zuckerberg (C) Sundar Pichai (D) Vishal Sikka

95.

Who invented Radio ? (A) Gugliemo Marconi (C) J.L. Baird

(B) Graham Bell (D) Benjamin Franklin

96.

Great English poet William Shakespeare belongs to which country ? (A) America (B) California (C) England (D) Ireland

97.

Which Salman Khan film is also the title of an Oscar winning song ? (A) London dreams (B) Tere naam (C) Jai ho (D) Maine Pyar kiya Paper Code: UN 418

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C L A S S : VIII

98.

What does the acronym KFC stand for ? (A) Kansas Fried Chicken (B) Kentucky Fried Chicken (C) Kansas Food Court (D) Kentucky Food & Chicken

99.

Often used as a slogan , what is the meaning of the word ‘inquilab’ ? (A) Surrender (B) Victory (C) Revolution (D) Long Life

100.

Where is the headquarter of International Olympic committee located ? (A) French (B) Switzerland (C) USA (D) England Space fo r rou gh w ork

Paper Code: UN 418

24

CLASS : 8

Class : 8

Mathematics

1.

If the sum of three consecutive even numbers is 234, which is smallest among them ? (A) 76 (B) 78 (C) 80 (D) 68

2.

If x + y = 6 and 3x – y = 4, find the value of x – y. (A) –1 (B) 0 (C) 2 (D) 4

3.

Which solid has the least number of faces ?

(A)

(B)

(C)

(D) Space fo r rou gh w ork

Paper Code: UN421

1

CLASS : 8

4.

What is the length of the diagonal of a square whose area is 16900 m2 ? (A) 130 m

(B) 130 2m

(C) 169 m

(D) 144 m

5.

A train is moving at a uniform speed of 75 km/hr. How far will it travel in 36 minutes ? (A) 60 km (B) 40 km (C) 50 km (D) 45 km

6.

ABCD is a rhombus. C 12 B

NO

y

D

5 z

A

Find the respective values of ‘x’, ‘y’ and ‘z’. (A) 12, 5, 13 (B) 5, 12, 13 (C) 5, 13, 5 (D) 12, 13, 5 Space fo r rou gh w ork

Paper Code: UN421

2

CLASS : 8

7.

No matter what two intergers I choose, their squares cannot differ by (A) 2016. (B) 2015. (C) 2014. (D) 2013.

8.

Evaluate the product 5 4 × (125)0.25.

1

(A)

#

(C) # #

(B) 5 (D) 25

9.

Which is the smallest natural number which when added to the difference of squares of 17 and 13 gives a perfect square ? (A) 1 (B) 5 (C) 11 (D) 24

10.

If a merchant estimates his profit as 20% of the selling price, what is his real profit percent ? (A) 25% (B) 20% (C) 22% (D) 30% Space fo r rou gh w ork

Paper Code: UN421

3

CLASS : 8

11.

12.

5 ⎞⎛ 15 25 ⎞ ⎛ + 2⎟ Find the value of the product ⎜ 3 + ⎟ ⎜ 9 − N ⎠⎝ N N ⎠ ⎝ at x = 1. (A) 150 (B) 148 (C) 152 (D) 172 Arif, Ajay and Madhav secured m + 20, 2m – 17 and m – 5 marks respectively in a Maths test. What is their average marks ? (A)

4m − 8 3

(B)

4m − 2 3

(C)

4m + 8 3

(D)

4m + 2 3

Space fo r rou gh w ork

Paper Code: UN421

4

CLASS : 8

13.

The pictogram shows the number of visitors to an exhibition in a particular week. Monday Tuesday Wednesday Thursday Friday

Key: Each

represents 6 visitors.

What is the number of visitors recorded after Wednesday ? (A) 10 (B) 18 (C) 60 (D) 70 14.

The difference of the cube and the square of a natural number is 48. Find the number. (A) 6 (B) 5 (C) 4 (D) 8 Space fo r rou gh w ork

Paper Code: UN421

5

CLASS : 8

15.

From a cuboid measuring 7 cm by 8 cm by 9 cm, a cube of side 5 cm is cut. What is the volume of the remaining cuboid ? (A) 397 cm3 (B) 389 cm3 (C) 398 cm3 (D) 379 cm3

16.

The product 1.25 × 10n is the cube of an interger when n=? (A) 2011 (B) 2015 (C) 2018 (D) 2016

17.

What is the sum of the greatest and the least numbers of 5 1 11 , and ? 9 9 9 2 4 4 2 (A) (B) (C) (D) 9 9 3 3 Space fo r rou gh w ork

Paper Code: UN421

6

CLASS : 8

18.

The marked price of an article is x, and selling price is y. What is the discount percentage ? (A)

( x − y )100 % x

⎛O− N⎞ (C) ⎜ O ⎟  ⎝ ⎠

(B)

(y − x )100 %

(D)

x−y % 100

x

19.

The area A, of a solid is given by the formula A = π r2 + 2 π rh + π rl. Find the value of A given that π = 3.142, r = 10, h = 3 and l = 4. (A) 629 (B) 628.4 (C) 630 (D) 631

20.

Which one of the following is the net of a cube ?

(A) 21.

(B)

(C)

(D)

How many different positive integers are factors of 36 ? (A) 3 (B) 6 (C) 7 (D) 18 Space fo r rou gh w ork

Paper Code: UN421

7

CLASS : 8

22.

If the areas of three adjacent faces of a rectangular block are in the ratio of 2 : 3 : 4 and its volume is 9000 cm³, what is the length of the shortest side ? (A) 10 cm (B) 15 cm (C) 20 cm (D) 30 cm

23.

Given that 512 = 83 and 3.375 = 1.53, find the value of 3 512 × 3 3.375 . (A) 12

(B) 9.5

(C) 8

(D) 1.5

24.

In a square ABCD, the diagonals bisect at O. What type of a triangle is AOB ? (A) An equilateral triangle. (B) An isosceles but not a right angled triangle. (C) A right angled but not an isosceles triangle. (D) An isosceles right angled triangle.

25.

If (25)N = (125)y, find x : y. (A) 1 : 1 (B) 2 : 3 (C) 3 : 2 (D) 1 : 3 Space fo r rou gh w ork

Paper Code: UN421

8

CLASS : 8

Class : 8

Physics

26.

Which part prevents internal reflections of light inside the human eye ? (A) Iris (B) Pupil (C) Choroid (D) Blind spot

27.

What is the distance between two consecutive rarefactions or compressions called ? (A) Amplitude (B) Wavelength (C) Time period (D) None of these

28.

In which component of a racing car is friction not desirable ? (A) Disc brakes (B) Engine (C) Tyres (D) Cover of steering wheel

29.

Static electricity is due to (A) charges in motion. (C) neutral charge.

30.

(B) charges at rest. (D) both (A) and (C)

Which action involves forces (that act on an object in two different directions), is similar to the one exerted when a pair of scissors cuts cloth ? (A) Pushing a cork stopper into the mouth of a glass bottle (B) Tearing a piece of paper (C) Erasing pencil marks from a worksheet (D) Hammering nails into the wall Space fo r rou gh w ork

Paper Code: UN421

9

CLASS : 8

31.

Identify a true statement about an electrolytic cell. (A) Electric current enters and leaves the electrolytic cell through the electrodes. (B) The electrode that is connected to the positive terminal of the battery is called the anode. (C) The electrode that is connected to the negative terminal of the battery is called the cathode. (D) All the three

32.

Which action can still take place successfully in the absence of friction ? (A) Speeding up your bicycle (B) Bouncing a ball (C) Leaning a ladder against a wall (D) Striking a match stick.

33.

Identify the value of persistence of vision. (A) 1/10th of a second (B) 1/12th of a second (D) 1/20th of a second (C) 1/16th of a second

34.

Effect of force on an object cannot change the (A) time. (B) shape. (C) speed. (D) direction of motion.

35.

Identify the energy change that takes place in a voltaic cell. (A) Chemical energy heat energy (B) Heat energy chemical energy electrical energy (C) Chemical energy (D) Electrical energy chemical energy

36.

Which property of sound is indicative of its loudness ? (A) Frequency (B) Pitch (C) Amplitude (D) Quality

Paper Code: UN421

10

CLASS : 8

37.

Where is the crust of the earth, the thickest ? (A) At the continents (B) At the ocean (C) At the poles (D) Near faults

38.

Material Y becomes negatively charged after it is rubbed with fur as it (A) gains positive ions. (B) gains electrons. (C) loses positive ions. (D) loses electrons.

39.

Identify the speed of sound in ascending order. (A) Air, water, steel (B) Steel, water, air, (C) Air, steel, water (D) Water, air, steel

40.

Which circuit gives the correct way of connecting an LED to light it up ?

(A)

(C)

5

5

(B)

S

(D)

5

Space fo r rou gh w ork

Paper Code: UN421

11

CLASS : 8

41.

A ball is rolling up a ramp when a force is applied on it. After rolling for a distance, it will come to a stop. What causes the ball to stop ? (A) Gravitational force (B) Frictional force (C) The shape of the ball (D) Both (A) and (B)

42.

Nocturnal animal like owl can see well in the night due to large (A) cornea and pupil. (B) number of rods in retina. (C) number of cones in retina. (D) both (A) and (B)

43.

The following are graphs of distance versus time when the same amount of force is applied in each case. 1

2 3

Distance

4 Time

Which one has the greatest amount of friction ? (A) 2 (B) 1 (C) 4 (D) 3 Space fo r rou gh w ork

Paper Code: UN421

12

CLASS : 8

44.

Which planet takes the maximum time to rotate around itself ? (A) Mercury (B) Pluto (C) Venus (D) Neptune

45.

The diagram given below shows a positive point charge in between a positively charged object and negatively charged object.

+

+

`

In which direction will the positive point charge move ? (A) Up (B) Down (C) Right (D) Left 46.

It is difficult to move a bike with its brakes on because (A) rolling friction will be converted to sliding friction (B) sliding friction will be converted to rolling friction (C) rolling friction will be converted to static friction (D) none of these

47.

Identify an application of ultrasound. (A) To scan the womb of a pregnant lady (B) To break up kidney stones and gall stone (C) To detect flaws in metals (D) All the three

48.

Which characteristic of an image formed by a plane mirror of an object is not correct ? (A) Virtual (B) Erect (C) Of same size (D) Real

Paper Code: UN421

13

CLASS : 8

49.

Why is zinc better than tin for electroplating a piece of iron in order to prevent it from rusting ? (A) Zinc is cheaper than tin. (B) Tin is toxic. (C) Zinc can prevent iron from coming into contact with water and air. (D) Rusting is prevented even when the zinc layer is broken.

50.

We (A) (B) (C) (D)

are deliberately using frictional force to sharpen a knife with a sharpening stone. crush garlic using a pestle and mortar. remove ice cubes from a tray. turn on the tap to wash dishes. Space fo r rou gh w ork

Paper Code: UN421

14

CLASS : 8

Chemistry

Class : 8 51.

The separation of the various fractions of petroleum is carried out in a/an (A) petroleum deposit. (B) oil reservoir. (C) petroleum refinery. (D) petrol pump.

52.

Carbon monoxide is produced when fuel is burnt with insufficient amount of oxygen. In excessive amount, why could this become harmful to humans ? (A) It blocks the transmission of signals in the nervous system. (B) It causes irritation in the respiratory system. (C) It damages the kidney and prevents secretion of waste from the body. (D) It binds with haemoglobin and disturbs the circulation of oxygen in the body.

53.

Which substance reacts with hydrochloric acid to give hydrogen ? (A) Ammonia (B) Iron (C) Silver (D) Sodium hydroxide

54.

What is a disadvantage of recycling metals ? (A) Collection and transportation incur cost. (B) Metal ores are a finite resource. (C) Most metals corrode slowly in the environment. (D) Scrap metal melts when heated.

55.

Identify a non-polluting fuel used in vehicles. (A) Petrol (B) Diesel (C) Kerosene (D) CNG

Paper Code: UN421

15

CLASS : 8

56.

Liquefied petroleum gas (LPG) burns with a (A) non-luminous flame. (B) luminous flame. (C) red flame. (D) orange and smoky flame.

57.

Which non-metal is used as an antiseptic to heal wounds ? (A) Carbon (B) Oxygen (C) Nitrogen (D) Iodine

58.

Rayon is different from synthetic fibres because it (A) has silk like appearance. (B) is obtained from wood pulp. (C) is obtained from petrochemicals. (D) is a strong fibre.

59.

Which statement is false ? (A) Kerosene is a fossil fuel (B) Coal tar is composed of a single constituent (C) CNG is less polluting than petrol (D) Both (B) and (C)

60.

Identify a true statement about the characteristics of incomplete combustion. (A) Insufficient oxygen is used to oxidise the carbons. (B) Insufficient heat is supplied to burn the coals. (C) Only one final product can be obtained, namely carbon dioxide. (D) Both (B) and (C)

Paper Code: UN421

16

CLASS : 8

61.

Which metal, attached to an iron pipe and immersed in seawater, would prevent rusting of the iron ? (A) Copper (B) Lead (C) Magnesium (D) Silver

62.

When we burn wool, we get the smell of burning of hair, because it is obtained from (A) nylon. (B) cotton plants. (C) jute plants. (D) fleece of sheep.

63.

The flame produced by a fuel depends upon the (A) calorific value. (B) amount of oxygen. (C) chemical composition. (D) all of the above

64.

Which of these is not a fossil fuel ? (A) CNG (B) LPG (C) Petrol (D) Hydrogen

65.

Aluminium combines with oxygen in the air to form a layer of dull-looking aluminium oxide. The aluminium beneath the oxide layer remains shiny. Which observation is not true ? (A) A chemical reaction has taken place, resulting in the formation of a new substance. (B) Energy is required for this change to take place. (C) The change is reversible, as shown by the shiny aluminium under the oxide layer. (D) The molecules of the oxide layer come from both aluminium and oxygen.

Paper Code: UN421

17

CLASS : 8

66.

Which polymer is chemically least reactive and thermally most stable ? (A) PVC (B) Teflon (C) Polythene (D) Nylon

67.

If the temperature falls below its ignition temperature, then what happens to the burning substance ? (A) It gets extinguished. (B) It burns brightly. (C) It burns dimly. (D) It burns with smoke.

68.

Identify the type of fuel that leaves more smoke and ash on burning. (A) Solid (B) Liquid (C) Gaseous (D) All of the above

69.

Electrical switches are made from (A) polythene. (B) bakelite. (C) china clay. (D) melamine

70.

Identify a property of non-metals. (A) They have low densities (B) They have low melting points (C) They are poor conductors of electricity (D) All the three Space fo r rou gh w ork

Paper Code: UN421

18

CLASS : 8

Class : 8

Biology

71.

Which of these are called weeds ? (A) Microbes (B) Unwanted plants (C) Insects (D) Fungal pest

72.

The gland that plays a key role in the metamorphosis of frog’s tadpole is (A) thymus. (B) thyroid. (C) adrenal. (D) pancreas.

73.

Which statement is true about migration ? (A) The phenomenon of restocking of destroyed biodiversity (B) The movement of animals to get protection from preying animals. (C) The phenomenon of movement of a species from its own habitat to some other habitat for a particular period. (D) The phenomenon of changing body colour and patterns.

74.

Which cell organelle is pigmented ? (A) Mitochondria (B) Golgi bodies (C) Nucleus (D) Plastids

75.

Which term is associated with rearing of fishes ? (A) Pisciculture (B) Poultry (C) Apiculture (D) Sericulture

76.

Which of these contain chloroplasts ? (A) Cycas (B) Mucor (C) Mushroom (D) Mould

Paper Code: UN421

19

CLASS : 8

77.

Red data book contains list of (A) endangered species of plants and animals. (B) extinct animals and plants. (C) exotic plants and birds. (D) rare species of plants and animals.

78.

Which of these distribute genetic information ? (A) Chromosomes (B) Ribosome (C) Lysosome (D) Peroxisome

79.

Fertilisation is external in (A) birds and fish. (B) amphibians and birds. (C) reptiles and fish. (D) fish and amphibians.

80.

What is the use of machinery in agriculture ? (A) Increase the quantity of crop yield. (B) Get the job done faster. (C) Reduce the dependency on human and animal labour. (D) Both (B) and (C)

81.

Which of these parts has nitrogen fixing bacteria in legumes ? (A) Leaves (B) Flowers (C) Root nodules (D) Stems

82.

Identify the longest cell in human body. (A) Nerve cell (B) Muscle cell (C) Bone cell (D) Gland cell

Paper Code: UN421

20

CLASS : 8

83.

Identify W, X and Y ?

W

9 (A)

Virus

(B) Algae (C) Virus (D) Fungus

X

: Protozoan Bacterium Fungus Algae

Y

; Fungus Virus Protozoan Bacterium

84.

Which organism can perform photosynthesis ? (A) Euglena (B) Amoeba (C) Mucor (D) Mushroom

85.

What is the direction of energy flow in an ecosystem ? (A) Multidirectional (B) Unidirectional (C) Bidirectional (D) Circular Space fo r rou gh w ork

Paper Code: UN421

21

CLASS : 8

86.

The number of ova released at a time in the female human being mostly is (A) 4. (B) 3. (C) 2. (D) 1.

87.

Adrenal gland in mammals is located (A) near pituitary. (B) near liver. (C) near heart. (D) above kidney.

88.

Which microorganism causes common cold ? (A) Bacteria (B) Virus (C) Protozoa (D) Algae

89.

Which of these is oviparous ? (A) Echidna (B) Bat (C) Cat (D) Rat

90.

What will be the genetic material found in a sperm ? (A) 22 + XX (B) 22 + Y (C) 23 + XY (D) None of these Space fo r rou gh w ork

Paper Code: UN421

22

CLASS : 8

Class : 8

General Awareness

91.

Which country will host the ICC World Twenty 20 tournament in 2016 ? (A) Srilanka (B) India (C) Australia (D) England

92.

Who is the founder of the Reliance Industries ? (A) Mukesh Ambani (B) Anil Ambani (C) Akash Ambani (D) Dhirubhai Ambani

93.

Which of the following is not a social networking website ? (A) Twitter (B) Facebook (C) Google+ (D) Wikipedia

94.

Complete the line of this song promoting national integration. " Mile sur mera tumhaara, toh _______ ". (A) sur saje tumhara (B) raag bane hamara (C) sur bane hamara (D) pyaar badhe hamara

95.

What is the purpose of Prime Minister's 'Make in India' campaign ? (A) Economic growth (B) Cultural growth (C) Social growth (D) Scientific growth

96.

“Vakratunda mahakaya, suryakoti samaprabha, nirvighnam kuru mey deva, sarva karyeshu sarvada ” is sung in praise of whom ? (A) Shiva (B) Rama (C) Ganesha (D) Krishna

97.

Which of these memorials is located in the capital city of an Indian State ? (A) Taj Mahal (B) Jallianwala Bagh (C) Gol Gumbaz (D) Charminar Paper Code: UN421

23

CLASS : 8

98.

The given logo belongs to which company ? (A) BMW (B) Toyota (C) Chevrolet (D) Renault

99.

Which of these is not a feature of facebook ? (A) Like (B) Timeline (C) Poke (D) Retweet

100.

Which of these is held annually in India ? (A) Lok Sabha Elections (B) Presidential Elections (C) Budget Session of Parliament (D) Vidhan Sabha Elections Space fo r rou gh w ork

Paper Code: UN421

24

UNIFIED COUNCIL A n I S O 9 0 0 1 : 2008 C e r t i f i e d O r g a n i s a t i o n

NATIONAL LEVEL SCIENCE TALENT SEARCH EXAMINATION - 2015 (UPDATED) Paper Code: UN412 Solutions for Class : 8 Mathematics 1.

(B)

∠ DAB = ∠ DAC + ∠ CAB = 60o + 60o

(a + b) (a + b2)(a – b)(a4 + b4) 2

= 120o

= (a2 + b2)(a + b)(a – b)(a 4 + b4)

7.

= (a2 + b2)(a2 – b2)(a4 + b4)

(C)

4xy = 84 ⇒ xy = 21

= (a4 – b4)(a4 + b4)

8.

= a8 – b8

(A)

2.

(D)

3.

(B)

We have, M1 = 10, D1 = 2, W1 = 15

When ‘n’ is added before 7, the 4th term is 6. When ‘n’ is added after ‘7’, the 4th term is 7. Hence, median can be either 6 or 7.

M2 = 10 – 2 = 8, D2 = 3, W2 = ?

9.

∴ M1D1W2 = M2 D2W1

(C)

10 × 2 × W2 = 8 × 3 × 15 Hence, 18 trees will be cut in 3 hours. When x = 0, the given statement does not satisfy.

10. (B)

(A)

Let

1 unit → 28 ÷ 10 = 2.8 2 units → 2 × 2.8 = 5.6

x 162 = x 128

3 units → 3 × 2.8 = 8.4 4 units → 4 × 2.8 = 11.2

Then, x2 =

Perimeter

128 × 162

=

64 × 2 × 18 × 9

=

82 × 62 × 32

Total number of units → 2 + 3 + 1 + 4 = 10 10 units → 28

∴ For x = 0, the given statement is false.

5.

S.I. on ` 800 for 1 year = ` (840 – 800) = ` 40  100 × 40  ∴ Rate =  800 × 1  % = 5%  

⇒ W2 = 18 trees

(B)

The median of seven numbers is 4th term. In the given list 4th term is 7.

a −b (a – b) ÷ c = + c c

4.

(x + y)2 – (x – y)2 = 100 – 16

=

22 5.6 22 8.4 22 2.8 × + × + × 7 2 7 2 7 2 +

= 8 × 6 × 3 = 144 ⇒ x = 12 6.

(B)

AB = BC = AC ∴ ∠ CAB = ∠ B = ∠ BCA = 60o

.... (i) 11. (D)

Similarly, ∆ ADC is equilateral ∴ ∠ DAC = ∠ D = ∠ DCA = 60o

..... (ii)

From (i) and (ii), we get website : www.unifiedcouncil.com

22 11.2 22 28 × + × = 88 cm 7 2 7 2

12. (A)

Since, tank P is half-filled, amount of water

7 = 0.777 9 9 = 0.818 11

∴ Water in tank Q = 900 cm3

⇒ 10 × 9 × h = 900

11 = 0.846 13

h = 10 cm Hence, height of water in tank Q is 10 cm.

∴ 0.777 < 0.818 < 0.846 ∴

1800 = 900cm3 2

=

19. (B)

7 9 11 < < 9 11 13

13. (B)

Clearly, 9261 is a perfect cube satisfying the given property.

14. (D)

In parallelogram ABCD,

Time taken to hear the sound 3 km 1 = 1200km / hr = 400 hr =

∠ A + ∠ D = 180o

= 9 seconds

Let ∠ D = x , ∠ A = 2x – 30 o

o

20. (C)

Since, equation in option (C) has a degree of ‘2’. Hence, it is not a linear equation.

21. (D)

2x + 3x + 4x = 180o

∴ (2x – 30 ) + x = 180 o

o

o

o

210o ⇒ 3xo = 210o or x = 3

9x = 180o x = 20o

∴ xo = 70o

∴ 4x – 2x = 2x = 2 × 20o = 40o

∴ ∠ D = 70o = ∠ B

and ∠ A = 2x – 30o = 110o = ∠ C 15. (C)

1 × 60 × 60 seconds 400

22. (D)

90 : 1080 = 120 : x B 1 0

90 120 = 1080 x ∴ x=

16. (B)

5

120 × 1080 = 1440 90

A

544 = (27 × 2)4 = (33 × 2)4

Length of AO =

= 312 × 24 23. (C)

186 = (9 × 2)6

5+1 = 6

Given a bc = 5 , ab2 = 56 2

3

3

∴ (a2bc3)(ab2) = (53)(56)

= (32 × 2)6

⇒ a3b3c3 = 59

= 312 × 26

⇒ abc = 53

456 = (9 × 5)6 = (32 × 5)6 = 312 × 56 ∴ 2112 is the greatest.

∠ D = ∠ BCD = ∠ ABC = 5x

only for x = 30o, ∠ ABC satisfies. Volume of tank P = 15 × 10 × 12 = 1800 cm3

 800 − 700   × 100 = 12.5%  800 

24. (A)

Discount % = 

25. (B)

4(a – b)2 – 9(b – c)2 = 22(a – b)2 – 32 (b – c)2

From the given options, 18. (D)

1+4 = 5

Length of AB =

2112 = (3 × 7)12 = 312 × 712

17. (A)

2

1

= {2(a – b)}2 – {3(b – c)2} = (2a – 2b)2 – (3b – 3c)2 = (2a – 2b + 3b – 3c) (2a – 2b – 3b + 3c) = (2a + b – 3c) (2a – 5b + 3c)

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Physics 26. (B)

27. (A) 28. (C)

29. (C)

30. (C)

31. (C)

32. (B) 33. (D)

Sounds higher than 20 kHz are called ultrasounds. Ultrasounds have high pitch (frequency) than the human audible frequency. So, ultrasounds cannot be heard by the human ear because the pitch (frequency) of the sound is too high. Streamline or torpedo shape will give the least resistance when moving through water. A series of fast moving still pictures can create an illusion of movement in our eyes. The impression of an image does not disappear immediately from the retina of the eye. It persists on the retina for about 1/16th of a second. So, if still pictures (images) of a moving object are flashed on the eye at a rate faster than 16 per second, then the eye perceives this object as moving. When the second image is flashed on the retina within a time less than 1/16th of a second, the brain cannot distinguish them as two images and takes them as continuity. So, the eye can separate two images only when the interval of separation between them is 1/16th of a second. This happens due to a phenomenon called persistence of vision. Point charge 1 and point charge 3 are positive charges. Point charge 2 is a negative charge. Since, unlike charges attract, point charges 1 and 2, point charges 2 and 3 will attract. According to the given graph, spring S is the strongest as it could stretch or extend upto 5 cm only when a load of 400 g was added to the pan attached to the spring. Type of spring

Weight

Stretching of spring in cm

(A)

P

170 g

10 cm

(B)

Q

240 g

8.5 cm

(C)

R

320 g

6.5 cm

(D)

S

400 g

5.0 cm

The point nearest to the eye at which an object is distinctly visible is called the near point of the eye. The distance of the near point of the eye is called the least distance of distinct vision. It varies with age. For an infant, it is 5 to 8 cm, for an adult, it is 20 to 25 cm. The ball travels a longer distance on the mirror as it is smooth and offers least friction. The given figure shows the process of electroplating. When electric current is

passed through copper sulphate solution, copper sulphate dissociates into copper (cations) (+ ions) and sulphate (anions) (– ions). The free copper ions are deposited on the carbon rod (cathode) which is connected to the negative terminal of the battery. Copper ions lost from the copper sulphate solution are replaced with the copper atoms from the anode (the copper plate). Net result is that the concentration of the electrolyte (copper sulphate salt in solution) remains the same. In the process, it is the anode which loses the metal atoms to the electrolyte which in turn gets deposited on anode. The metal plate gradually gets degenerated.

34.

35.

36.

37. 38.

+ + water CuSO4  → Cu + SO4 (in solution form) Copper Copper Sulphate sulphate (Cations) (anions) (salt) Copper cations get deposited on cathode. Sulphate ions react with copper on copper plate to form copper sulphate. Due to the above reason, the mass of electrode (copper plate) decreases. (B) X is liquid mercury which is filled in the syringe. When the plunger is pushed inwards, there is no change in volume of mercury. A liquid cannot be compressed much due to its high density and also its particles are still quite close together by slightly, weak, interparticle force of attraction. Helium, Nitrogen and Carbon dioxide are gases at room temperature and they can be compressed easily. (C) Some times at night, we observe small glowing objects rapidly falling down from the sky. They are masses of rocks and minerals falling from the outer space and are called meteors. Meteors enter into the earth’s atmosphere with high speed. Due to friction of air, they get heated up. They burn leaving behind a streak of light which appears like a shooting star. The remains of some of the meteors reach the earth as meteorites. (B) We know that for a reflected ray, the angle that the incident ray makes with the line perpendicular to the surface is equal to the angle made by the reflected ray with this perpendicular line. N is the correct reflected ray of X. (B) Protons are positively charged and electrons are negatively charged. (B) Stars in the sky differ in size, colour, temperature and brightness. The colour of a star depends upon its surface

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39. (C)

40. (A)

41. (A)

42. (C)

43. (A)

temperature. Blue stars are the hottest with a surface temperature between 28000 – 30000 oC. In solid state, potassium iodide does not conduct electricity because the potassium (K +) ions and iodide (I – )ions are held together by strong electrostatic forces of attraction. In molten state, the respective ions are set free. During electrolysis the K+ ions move towards the cathode and I– ions move towards the anode. This property of ions K+ I– and starch solution is used in an electric pen for writing on the surface with special compounds and material. KI → K+ + I– Two columns, air column and water column respectively are formed in four bottles P, Q, R and S, which are filled with different volumes of water. When air is blown into the four bottles separately, sounds of varying loudness are produced. (i) The bottle with least level of water has longest air column above water and has low frequency and low pitch. So, feeble sound is produced. (ii) The bottle with highest level of water has least air column above water and has high frequency and high pitch. So, loud sound is produced. (iii) In jaltarang musical instrument, the cup containing minimum water produces the sound of lowest frequency. As the amount of water in the cup goes on increasing, the frequency of the sound produced also goes on increasing. The correct sequence of increasing loudness of sound in bottles P, Q, R and S is R → P → Q → S. In voltaic cell, copper plate acts as anode (+) and zinc plate acts as cathode (–). Electric current is produced inside the cell through the electrolyte, dilute H2SO4 which passes through electric wires from anode to cathode outside the cell. So, when two copper plates are used as electrodes in the voltaic cell, electric current is not produced. There are several effects of forces : (i) Change the speed of an object (option A) (ii) Change the direction of motion of an object (iii) Change the energy of the system (option B) (iv) Change the shape of an object (option D) Pitch is measured in hertz.

44. (D)

45. (D)

46. (B)

47. (C) 48. (B)

49. (D)

50. (B)

Object distance after shifting the object = 4 m + 0.5 m = 4.5 m For a plane mirror; Object distance = Image distance = 4.5 m Distance between the object and its image = 4.5 + 4.5 = 9 m The free electrons in the conducting sphere are being repelled to the right by the negatively charged rod. The protons are fixed in the nucleus and the nucleus is not free to move from its fixed position in the conducting sphere. So, the protons in the conducting sphere do not move. Among the given solutions, sodium chloride is a strong electrolyte because it ionizes completely. NaCl (Sodium chloride) solution allows current to pass through it as it contains positively charged sodium (Na+) and negatively charged chloride (Cl–) ions. When current is passed through strong electrolyte like sodium chloride, the bulb will glow the brightest. Ammonium hydroxide and ethanoic acid are weak electrolytes because they do not ionize completely. So, the bulb does not glow brightly when weak electrolytes are used Alcohol is a non-electrolyte as it has no ions to conduct electricity. Since, surface 3 needed the greatest force to move the object, this surface is the roughest. The loudness of a note on the guitar can be increased by increasing the amplitude of the vibration of the guitar spring. Options (A) (C) and (D): Changes in tension, thickness and length of the guitar string affect the pitch or frequency of the sound, not its loudness. When a force acts on small contact area, the pressure is high. Sharp things are able to penetrate because of the small contact area. Knife, scissor, hole punch, thumb tack, saw and many other tools make use of the small contact area to penetrate due to high pressure. Hammer transmits force and energy but it is not normally used to create high pressure to penetrate through things. The electrons on the underside of the lightning cloud induce a positive charge on the earth’s surface. When the electric field is strong, the electrons are being attracted to the earth. Lightning is caused by large amount of fast moving electrons moving at high speed through the air from the cloud to the ground.

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51. (B)

52. (A)

53. (D)

54. (B)

55. (A)

56. (B)

57. (A)

Chemistry According to the bar chart, people of cities I and IV should wear masks when they go outside as the amount of pollutants in particle and gaseous form is very high. Inhaling polluted air by human beings and animals leads to many respiratory problems. The given figure shows the deposits of petroleum and natural gas. These deposits are present in the impervious rock situated deep in the earth. They are formed based on their densities. Natural gas being lighter occupies the top most layer followed by petroleum (crude oil). Water being denser than gas and oil occupies the bottom of the fossil fuel deposits. ‘P’ is petroleum below the natural gas ‘Q’. Potassium and sodium are very reactive metals. Zinc and iron are less reactive than potassium and sodium. Lead is less reactive than zinc, iron and tin. As we come down in the series, the chemical reactivity of metals decreases. So, the descending order of reactivity of metals is sodium, zinc and lead. Since, the mass of material Q does not change much when it is soaked in water, it is the least absorbent. A swim suit should be made of the least absorbent material so that water does not add much to the mass of the swim suit. Sulphur is an impurity in coal. When coal is burnt in power plants, sulphur dioxide gas is released along with other gases. Sulphur dioxide gas reacts with the water vapour in the atmosphere to form sulphuric acid. This acid falls down alongwith rain and makes it acidic as given below. Sulphur dioxide + water → sulphurous acid Sulphur trioxide + water → sulphuric acid Burning of paper releases carbon dioxide. Use of CFC products damages the ozone layer of the atmosphere but it is not the cause are source of acid rain. Rust or iron(III) oxide can be removed by reaction with acids. Concentrated sulphuric acid does not have strong acidic properties, unlike lemon juice (contains citric acid), as there is incomplete dissociation of the acid due to lack of water. Dilute sulphuric acid not concentrated is more effective to remove the rust on the steel object before painting. Use of water and aqueous sodium hydroxide (a base) cannot clean a rusty steel object thoroughly. When organic wastes are decomposed in the absence of oxygen, biogas is released. Biogas consists mainly 65% of methane and 35% of other gases like carbon dioxide,

58. (D)

59. (A) 60. (B)

61. (A)

62. (C)

63. (B)

hydrogen and hydrogen sulphide. When methane gas is released into the atmosphere, it causes air pollution. Carbon monoxide which binds to the haemoglobin prevents oxygen from binding. This causes reduction in the amount of oxygen circulated in the blood which in turn causes inadequate amount of oxygen distributed to the body. Carbon monoxide is poisonous. However it is difficult for us to detect due to its colourless, odourless and tasteless property. As per the given figures and statements, only statement (A) is true. City ‘R’ recycles 85% of its plastic wastes. Polypropene is used for making transparent containers, water pipes, pipe fittings, bodies of automobile batteries and toys. Polyethylene terephthalate (PET) is used for making microwave ovenware. Non-luminous flame has more heat than light because the fuel is completely burnt. It is not safe to leave a non-luminous flame burning because it is not visible. Lack of visibility may cause burns accidentally. Fuels burn in the presence of oxygen to form carbon dioxide and water vapour. (i) Magnesium burns in the presence of oxygen to form magnesium oxide. 2Mg + O2 → 2MgO (ii) Water combines with oxygen to form hydrogen peroxide. 2H2O + O2 → 2H2O2 (iii) Camphor when burnt undergoes sublimation and changes directly from solid to gas. Melamine is a type of thermoset plastic. It cannot be remoulded because it has cross links between the monomers as shown below.

Monomer Monomer Cross links

64. (C)

Linear chains

Copper and silver, both being lower down than hydrogen in the reactivity series are easily displaced out of a solution of their ions by reactive metals higher up in the reactivity series. Iron, however, cannot displace Mg2+ and Ca2+ as it is below Mg and Ca in the reactivity series. Fe + Cu2+ → Fe2+ + Cu Fe + 2Ag+ → Fe2+ + 2Ag

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65. (D)

66. (B)

67. (D)

68. (A)

69. (D)

70. (B)

71. (B) 72. (B)

Biodegradable rubbish buried in the ground decomposes to become nutrients that do not pollute the environment. Burning of trees in the forests produces carbon dioxide, ash and smoke that pollute the environment. Using treated waste from sewage plants to fertilise roadside trees is not a form of pollution, as harmful substances have been removed from the waste. Turning waste water into drinkable water is not a form of pollution. Statements (A), (C) and (D) are true of sodium. Sodium reacts vigorously with water at room temperature to form sodium hydroxide and hydrogen gas is released. 2 Na + 2H2O → 2NaOH + H2 Sodium hydroxide is a base. Bases change the colour of red litmus paper to blue. Carbon dioxide is the fourth most abundant gas found in air. It can react with water to form a weak acid, carbonic acid. This in turn causes the slight acidic property of rain water. Carbon dioxide is a non-pollutant gas that helps plants to carryout photosynthesis. During lightning, the free nitrogen reacts with oxygen in the atmosphere to form NO 2 (nitrite) and NO 3(nitrate) respectively. This salts ultimately reach the earth/soil which helps in the growth of plants. Excess of nitrate in the soil mixes with ground water and causes water pollution. Nylon is used for making a wide range of products like fine sarees, thread, ropes, fishing nets, carpets, seat belts, umbrella covers, parachutes etc. Polyethene is used for wrapping films. Polystyrene is used to make disposable foam cups. PVC is used for making floor tiles. Fire extinguishers are filled with liquid carbon dioxide under high pressure. It does not support burning. This gas must be sprayed on the top of the fire to put out the fire gradually. Spraying the CO2 gas at the bottom of the fire does not extinguish it but supports burning as it has more of oxygen than carbon. Statements (A), (C) and (D) are true of diamond. Diamond is a bad conductor of heat and electricity. Biology Harmful bacteria called mycobaacterium tuberculosis causes tuberculosis. Figures labelled (i) and (iv) are plants cells.

73. (C) 74. (C) 75. (A) 76. (C)

77. (D) 78. (D) 79. (A) 80. (B) 81. (A) 82. (A) 83. (A)

84. (A) 85. (C) 86. (D)

87. (C) 88. (A) 89. (D) 90. (A)

They have a rigid cell wall. Exchange of gases and transpiration of water vapour takes place through stoma. To conserve natural resources anyone who chops down a true to replant a new tree within the same. Farmer mixes fertiliser with water to enable the roots to easily absorb it. The quantity and quality of food production can be increased by using modern technology and carrying out research and development. All microorganisms are the organisms that cannot be seen with the naked eye. Menstruation does not take place during pregnancy. In the given figure the part labelled N is nucleus. Nucleus controls activities in cell. Butterfly undergoes 4 stage life cycle and a bird undergoes 3 stage life cycle and the mother provides food for the young. The sex chromosones of parents X and X fertilises to form a girl child. Yeast releases carbon dioxide gas and makes bread dough rise. The picture shown is a Euglena. It is fresh water free living unicellular organism. The long whiplike flagellum is used for swimming and it reproduces by splitting. It is bright green in colour as it contains chloroplast which allows Euglena to conduct photosynthesis. A virus is a microscopic organism. It cause diseases in plant cells and animal cells. It can reproduce only inside a living cell. Cells in reproductive organs undergo meiotic division to produce haploid cells or gametes. Sex of a child is determined by father, as the gamete have either X or Y chromosomes. X chromosome of father determine as a girl child & Y as a boy child. As the woman attain menopause stage, the ovaries cannot produce any more eggs hence, she cannot become pregnant. Paramecium is a protozoan. It is a microorganism. Presence of cell wall indicates that it is a plant cell. Ecologically fungi are important because they acts as decomposers and aid in nutrient cycling.

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UNIFIED COUNCIL A n I S O 9 0 0 1 : 2008 C e r t i f i e d O r g a n i s a t i o n

NATIONAL LEVEL SCIENCE TALENT SEARCH EXAMINATION Paper Code: UN415 Solutions for Class : 8 5.

Mathematics 1.

(A)

(A)

4o = 1 = 14 (Since ao = 1.)

(C)

770

S.P. of cycle = Discount =

(880 – 770) =

Discount percentage = 3.

(D)

d ∴ Cost of y metres = < ⎛⎜ × y ⎞⎟ ⎝N ⎠

880

M.P. of cycle =

⎛ yd ⎞ ⎟ ⎝ N ⎠

= 212.

= ` 135 – ` 108

The descending order is

= ` 27

4 2 1 3 6 , , , , . 9 5 6 4 7

The middle number is 4.

(B)

D

Hence discount allowed to gain 8% 27  100% = 20% 135

1 . 6

C

7.

(A)

The cube in option (A) can be formed by the given net.

8.

(B)

Area of trapezium

O

= A

B

1 (sum of parallel sides)  altitude 2

Let the other parallel side be x cm.

As shown in the figure, the angle bisectors of Α and D meet at O.

Then

o Let A = xo then D = 180  x  .



135 = ` 135 100

108 = ` 108 100 Discount allowed on ` 135

4

(C)

5 7  5 7  5  10 175 = = = 87.5 0.4 2 42 Let the C.P. of the article be ` 100.

M.P. = 100 

4

212 = 234 =  23  = 8 4 38 = 324 =  32  = 94

3.

343  125 73  53 =3 0.064  0.4 3

=

Therefore Sudhir ’s age 5 years ago = (x – 3 – 5) years

2.

3

A x and = 2 2

D 180o  x x = = 90o  2 2 2

x x AOD = 180o   + 90o   2 2   or AOD = 180o   90o  = 90o

websit e : www.unif iedcouncil.com 1

1 (x + 6)  4 = 28  x = 8 cm 2

9.

(D)

Let one of the numbers be x.

13. (A)

Then the second number = 3x

2  8 = 2  8 = 16 = 4 is a rational

p 22 is in the form of wheree q 7 p and q are integers and q  o.

number.

By the given condition, one number +15 = 2(second number + 15)

Therefore

i.e., 3x + 15 = 2(x + 15) or  3x + 15 = 2x + 30 or

14. (D)

ax = a10 and (ay)3 = ax . ay

Given

6x + 30 = x + 15  3x – 2x = 30 – 15 or



6x – x = 15 – 30 or 5x = –15 or x = –3

(ay )3 = a10 ay

 x = 15

 (ay)2 = a10

Hence, if one number is 15 the other number is 3  15 = 45. (or) if one number is –3, the second number is 3  (–3) = –9

 a2y = a10  2y = 10  y = 5 ax = (ay)3 = (a5)3 = a15  x = 15

 Of the given options 15 and 45 are the

required numbers.

15. (C)

0.081 0.484 2.5   0.0064 6.25 12.1

10. (A)

=

The more the radius, the less the number of rounds. Radius (cm)

810 484 25   64 6250 121

Rounds

20

260

1

260 × 20

26

260 × 20 26

81 484 25 =   64 625 121

16. (D)

= 200

9 22 5 =   = 0.45 8 25 11

The pentagon can be divided into 3 triangles by joining the vertex A to C and D (See the figure).

The angles for the different grades given

Angle sum of 1 triangle = 180o

are

Angle sum of 3 triangles

20  360o = 60o  (A) is correct; 120

= 3  180o = 540o

50  360o = 150o  (B) is correct; 120

Sum of the four equal angles

45  360o = 135o  (C) is correct. 120

Each equal angle

= 540o – 120o = 420o = 420o  4 = 105o 17. (A)

5  360o = 15o  (D) is incorrectly 120 labelled as 20o

a = 6 as 63 = 33 + 43 + 53

2

12. (B)

22 are rational 7

numbers.

2(3x + 15) = x + 15

11. (D)

2  8 and

1 1  2 x+  = x + 2 +2 x x  

= 79 + 2 = 81 x +

1 = 81 = 9 x websit e : www.unif iedcouncil.com 2

18. (A)

1 l = 1000 cm3

22. (A)

 1.5 l = 1500 cm3

Sides of the rectangle are (3p + 5q) units and (5p – 7q) units. Area of a rectangle = l  b

Volume of water in the tank = Area of the base  height

Area = (3p + 5q) (5p  7q)

= 3p(5p  7q) + 5q (5p  7q)

 1500 = 250  height  height =

1500 =6 250

= 15p2  21pq + 25pq  35q2 = 15p2 + 4pq  35q2 sq.units.

 Height of water in the tank = 6 cm 3 cm

5   Total height of the tank =  6 × 2  cm

23. (D)

3 cm 3 cm

= 15 cm. 19. (B)

Two cubes of dimensions 3 cm  3 cm are e placed side by side resulting in a cuboid of dimensions 6 cm  3 cm  3 cm.

Since x + xy = 391, then x(1 + y) = 391. We note that 391 = 17  23. Since 17 and 23 are both prime, then if 391 is written as the product of two positive integers, it must be 1  391 or 17  23 or 23  17 or 391  1.

24. (D)

108 = 2  2  3  3  3 = 22  33 192 = 2  2  2  2  2  2  3 = 26  31 108  192 = 22  33  26  31

Matching x and 1 + y to these possible factors, we obtain (x, y) = (1, 390) or (17, 22) or (23, 16) or (391, 0).

= 28  34  Sum of the powers = 8 + 4 = 12

Since y is a positive integer, the fourth pair is not possible.

25. (D)

Let original edge of the cube be ‘a’ units. Surface area = 6a2 sq.units.

Since x > y, the first two pairs are not possible.

Increase in edge = 25%

Therefore, (x, y) = (23, 16) New edge =

 x + y = 39 

20. (A)

328 = P  1 + 

 328 = P 

2

New surface area

 5    1 100  

2

75a2  5a  =  8  4 

= 6

41 400

Increase in surface area

 P = ` 3200

 75a2

3200  5  2  S.I. = ` = ` 320 100

21. (D)

=

 8

According to the problem, 8+

125 5a a = units 100 4

=

m = 4  3m 5



 6a2  

27a2 8

 Percentage increase in surface area

 40 + m = 5(4 – 3m)  27a2

 40 + m = 20 – 15m

=

 8

 20 = –16m  m=

= 56.25%

20 16

 m= 

5 4



websit e : www.unif iedcouncil.com 3

 1  100  % 2 6a 

against each other. When you move a table along the floor, frictional force opposes the motion of the table.

Physics 26. (D)

The angle between the horizontal plane and normal is 90 o. If the angle of incidence is 50o, then the angle between the incident ray and normal is 90o – 50o = 40o. Similarly, the angle between the normal and reflected ray on the other side will be 90 o – 50 o = 40 o. The angle between the incident ray and relfected ray = 40o + 40o = 80o as shown below. 40o 40 o

50

33. (A)

As the shiny aluminium foil is pasted on the outer surface of the ball, it behaves like a convex mirror. A candle placed in front of this shiny surface forms an image which is virtual, erect and smaller in size.

34. (D)

When the ball hits the floor, a pushing force acts on it and causes it to bounce. A turning force acts on the ball to make it spin as it moves through the air. Frictional force acts on the ball when it lies stationary on the floor.

o

50o

27. (B)

The audible range of sound that can be detected by the human ear is between 20 Hz to 20,000 Hz.

35. (C)

28. (C)

Friction between the tyres and the ground as well as between the shoes and the ground is needed for the car or the person to move. Friction between the brakes and the wheels on cars is also important, it has an important role to stop the car.

Solid sodium chloride does not conduct electricity as the sodium ions and chloride ions are not free to move and held firmly in fixed positions in the crystal.

36. (C)

Percussion instruments produce sound by vibrating a stretched membrane tightly stretched on the surface of tabla, drum, dholak, mridangam etc.

37. (C)

A gold leaf electroscope is used to detect, measure and find the nature of charge of a body.

38. (C)

An object contains both protons and electrons. It will become negatively charged when it gains electrons and contains more electrons than protons.

39. (D)

There are several effects of frictional force:

Friction between the parts in a machine is undesirable as it creates heat and causes the machine to be inefficient as there is mechanical energy lost to the surroundings. 29. (C)

30. (C)

31. (B)

32. (C)

An earthquake is a sudden shaking or trembling of the earth. It is so sudden that it cannot be predicted in advance. Both the earth and the moon exert gravitational force on each other. As the earth is larger than the moon, the gravitational force exerted by the earth is about six times that exerted by the moon. The moon is kept in orbit around the earth because of the earth’s gravitational force. The moon’s gravitational force pulls on the water in the earth’s oceans. The slight movement of water towards the moon results in tides.

It prevents slipping and sliding (option A). It produces heat, which could be useful or waste energy(option B). It causes wear and tear (option C). Phenomenon in option (D) is caused by electrostatic force.

Electrolytes are able to conduct electricity in molten state and in aqueous solution as they contain freely moving ions. Frictional force occurs when two rough surfaces are in contact with and slide

40. (A)

A voltaic cell consists of two electrodes made of different metals i.e., copper and zinc properly connected with wires and the electrodes are immersed in an electrolyte, dilute sulphuric acid.

41. (A)

Frictional force is one of the contact forces, which could only exist when there is a contact between two surfaces. Gravitational force, magnetic force, and electrostatic force could happen at a distance.

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42. (A)

The amount of light that is reflected depends on the nature of the surface on which the light falls and also on the material.

43. (A)

Amplitude is the maximum or the greatest distance that a vibration or the pendulum (weight) moves on either side from the zero point or mean position.

44. (C)

Stars are mainly made up of hydrogen and helium.

45. (C)

A comb acquires electrical charge on rubbing with dry hair and attracts bits of paper. The electric charges generated by rubbing are static, i.e., they do not move.

46. (B)

Friction, magnetism and weight are forces. Mass is not a force.

47. (B)

Sound needs a medium to transmit. The medium can be solid, liquid or gas. Sound cannot transmit through vacuum because there are no vibrating particles to pass on the energy. It is impossible for sound to be transmitted in space.

48. (B)

Three plane mirrors are arranged at an angle to get a number of coloured images in a kaleidoscope.

49. (D)

During the process of electrolysis, a compound is broken down into its constituent elements when electric current is passed through an electrolyte. Cations move to the cathode and discharge by accepting electrons from the cathode. Anions move to the anode and discharge by donating electrons to the anode.

50. (D)

calcium carbonate. In the presence of acid, calcium carbonate reacts with the acid to form salt, water and carbon dioxide. When acid rain comes in contact with limestone buildings and monuments, these reactions take place and in a long run cause the building and monuments to waste-away and be destroyed. 53. (A)

X cannot react with water, hence, it is below Ca in the reactivity series. X can react with acid; hence, it is above Cu in the reactivity series. XO cannot react with H2, hence, it is either Zn or below Zn in the reactivity series. XO can react with C; hence, it is Zn or below Zn in the reactivity series. From all the possible options, Zn is the only possible metal.

54. (D)

Polysaccharides is another term used for sugar. Sugar is formed by plants. Polyethylene and polyvinyl chloride are industrially manufactured polymers.

55. (A)

Product ‘P’ is coal gas which is obtained during the processing of coal to get coke. It was used for street lighting. But nowadays, it is used as a source of heat (fuel) in many industries located near the coal processing plants.

56. (B)

All complete combustions of organic materials will produce only carbon dioxide and water vapour. Other small molecules such as carbon monoxide and carbon ash are the byproducts of incomplete combustion.

When an object moves with constant speed, that implies equilibrium condition. In the case of the airplane described in the question, the thrust is equal to the drag, and the lift is equal to the weight.

57. (D)

Aluminium is a reactive metal that reacts readily with oxygen in air to form a protective layer of aluminium oxide which is impervious to water.

58. (B)

The rope must be strong enough to support the weight of the climber. It also needs to be flexible in order to go around corners and to be rolled up for easy carrying. The carabiner must be hard enough to keep its shape and strong enough to withstand the pressure of the rope going through it, as well as support the necessary weight.

59. (D)

Coal tar is used as a starting material for manufacturing synthetic dyes, drugs, napthalene, explosives, perfumes, plastics, paints, photographic and roofing materials.

Chemistry 51. (A)

The useful substances that are obtained from petroleum and natural gas are called petrochemicals.

52. (B)

The major proportion of limestone is

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60. (D)

Combustion of most of the fuels releases carbon dioxide into the atmosphere. If the concentration of this gas increases, it causes global warming. Global warming leads to a rise in atmospheric temperature and melts the ice on polar ice caps, glaciers etc., causing an increase in the sea level which is the main reason for flooding surrounding areas.

71. (D)

44 + XX represents the composition of femaledestined zygote in human beings.

72. (A)

Adrenaline hormone is secreted by the adrenal gland present on the kidney.

73. (D)

Budding, binary fission, spore formation are types of asexual reproduction.

74. (A)

Spirogyra is called pond silk.

75. (C)

The cell wall is made up of cellulose.

76. (C)

Malaria is a disease caused by protozoan plasmodium

77. (B)

The combustion in which heat, light and sound are produced is known as explosive combustion.

The figure given in option ‘B’ is chlamydomonas. Chlamydomonas is an aquatic photosynthetic organism.

78. (B)

Different varieties of coal have different carbon content.

Mitosis is an equational division. It helps in replacement of worn out cells.

79. (B)

Sodium has a density of 0.968 g cm –3. It floats and reacts violently with water.

Malaria is caused due to the entry of pathogen plasmodium

80. (C)

Hydrophytes like lotus have large, flat wax coated leaves and poorly developed root system.

81. (D)

The process of changing of tadpole into an adult is called metamorphosis.

82. (C)

Kerosene is obtained by fractional distillation of crude petroleum.

Cell membrane regulates the passage of wastes, water and food into and out of a cell.

83. (A)

PVC can be coated on cloth to give a water proof coating and is tougher than polythene.

Bacteria reproduces by fission, Mucor by spore formation, yeast by budding and spirogyra by fragmentation.

84. (B)

Thyroxine is iodine containing hormone.

85. (A)

Sandy soil contains large particles of soil hence it cannot hold water and is not good for plants to grow.

86. (D)

Fertilisation is external in fishes and amphibians.

87. (B)

Cuscuta is a parasitic plant.

88. (A)

Cell wall and chloroplasts are the organelles present only in plant cells.

89. (C)

Rice is a kharif crop.

90. (A)

Zygote  Embryo  Foetus  Baby is the correct sequence shown in sexual reproduction.

61. (B)

Steel is an alloy of iron which contains about 1-2% of carbon.

62. (B)

A cup made of styrofoam containing hot tea or coffee can be held in hands since it does not conduct heat.

63. (B)

64. (C) 65. (D) 66. (D)

Recycling reduces landfill rubbish and saves natural resources and energy.

67. (C)

Among the given fuels, hydrogen has the highest calorific value of 1,50,000 kJ/kg. Coal 25000 – 33000 kJ/kg, Petrol 45,000 kJ/ kg and CNG 50,000 kJ/kg.

68. (C) 69. (B)

70. (A)

Biology

The given figure is of an alloy called bronze. It is made by combining copper and tin.

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UNIFIED COUNCIL A n I S O 9 0 0 1 : 2008 C e r t i f i e d O r g a n i s a t i o n

NATIONAL LEVEL SCIENCE TALENT SEARCH EXAMINATION (UPDATED) Paper Code: UN 421 Solutions for Class : 8 Mathematics 1.

(A)

5.

(D)

Let the three consecutive even numbers be 2x – 2, 2x and 2x + 2. We have, (2x – 2) + 2x + (2x + 2) = 234  6x = 234  x = 39

2.

(A)

Time taken (in minutes)

60

36

So, it is a case of direct proportion.

x+y=6

 xy=

(B)

x

= 2x – 2 = 2(39) – 2 = 76

 Now,

 The distance covered in 36 minutes is

45 km.

5 7  = 1 2 2

6.

(B)

x = OB = OD (Diagonals bisect) = 5 y = OA = OC (Diagonals bisect) = 12

The solid in option (A) has only 4 faces which is the least compared to the other three.

z = side of the rhombus = 13 (All sides are equal). 7.

B

A

75 x 5 x  = = 60 36 4 36

5   x =   36  = 45 4 

5 15 7  x = ,y = 4= 2 2 2

4.

75

 The least even number

4x = 10

(A)

Distance covered (in km)

Since the speed is uniform, less distance will be covered in less time.

3x – y = 4

3.

Let the distance covered by the train in 36 minutes be x km.

(C)

2016 = 452 – 32 = 2025 – 9 = 2016 2015 = 482 – 172

D

= 2304 – 289

C

= 2015

Let the side of square be x m. Then

2013 = 472 – 142

x2 = 16900 m2

= 2209 – 196 = 2013  x=

16900  x = 130 m

Diagonal BD =

 No matter what two integers you choose, their squares cannot differ by 2014.

DC2 + BC2

= 1302 + 1302

= 130 2 m websit e : www.unif iedcouncil.com 1

8.

(B)

51/4  125 

0.25

= 50.25   53 

15. (D)

0.25

Volume of the cuboid = 7  8  9 = 504 cm3 Volume of the cube cut from the cuboid = 5  5  5 = 125 cm3

= 50.25  53×0.25

= 50.25  50.75

Therefore, volume of the remaining cuboid

= 5 0.25+0.75

= (504 – 125) cm3 = 379 cm3

= 51 = 5 9.

(A)

16. (B,C)

172 – 132 = 289 – 169 = 120

1.25  10n = 125  10–2  10n = 125  10n–2

120 + 1 = 121 = 112 10. (A)

= 53  10n–2

Suppose S.P. = ` 100

If 53  10n–2 is the cube of an integer then (n – 2) should be divisible by 3.

Profit = ` 20 C.P. = ` (100 – 20) = ` 80 Profit % =

=

11. (C)

Among the given options, if n = 2015, n – 2 = 2013 which is divisible by 3.

Profit  100% C.P.

If n = 2015, 1.25  102015 = 53  102013

20  100% = 25% 80

= 53  (10671)3 = (5  10671)3

5  15 25   At x = 1,  3 +   9  + 2  x  x x  

or if n = 2018, n – 2 = 2016 which is divisible by 3.

5  15 25   = 3+  9  +  1 1 1 

12. (B)

13. (C)

If n = 2018, 1.25  102018

= (3 + 5) (9  15 + 25)

= 53  102016

= 8  19 = 152

= 53  (10672)3 = (5  10672)3

Average marks =

m + 20 + 2m  17 + m  5 3



4m  2 3

17. (C)

The ascending order of given numbers is 1 5 11 , , . 9 9 9  The required sum 11 1 12 4 = + = = 9 9 9 3

No. of symbols representing the no. of visitors after Wednesday = 6 + 4 = 10

18. (A)

No. of visitors represented by each symbol = 6

M.P. = ` x S.P. = ` y Discount = M.P. – S.P.

Each symbol = 6

= ` (x – y)

 Total no. of visitorss

Discount% 

= 10  6 = 60. 14. (C)

Let the number be x. 

x3 – x2 = 48 19. (B)

x2(x – 1) = 48

Discount  100% M.P.

xy  100% x

When  = 3.142, r = 10, h = 3 and l = 4, A = 3.142(10) (10 + 2  3 + 4)

= 16  3 = 42(4 – 1)

= 31.42(20) = 628.4

x=4 websit e : www.unif iedcouncil.com 2

20. (B)

The net is option (B) is the net of a cube.

21. (C)

36

Friction in the brakes, tyres and steering wheel cover is necessary to provide better grip. Friction is not desirable in an engine.

=3  3  3  3  3  3  1 =9  3  3  3  3  1 = 27  3  3  3  1

29. (B)

Static electricity is the accumulation of electrical charges on the surface of a material, usually an insulator or a nonconductor. In static electricity, the charges stay on an object without flowing i.e., they are at rest.

30. (B)

When two or more forces act on an object in two different directions the effect on the object is due to the magnitude and direction of the net force acting on it. A piece of cloth is cut with the help of a scissor from bottom to the top and the cut pieces have regular and desired shape. Tearing a piece of paper with hand mostly occurs from top to the bottom and the torn pieces of paper do not have a regular and desired shape. Forces which act on a body in two different directions can cause the object to break, cut or tear.

31. (D)

All the statements are true about an electrolytic cell.

32. (B)

In option (A), friction is needed for the bicycle to start moving, stopping, slowing down and speeding up.

= 81  3  3  1 = 243  3  1 = 729  1  There are 7 different positive integers among the factors of 36.

22. (B)

Let the dimensions of the rectangular block be a, b and c. Given ab : bc : ca = 2 : 3 : 4 and abc = 9000 cm3 ab bc ca : : Now, abc abc abc 2 3 4 = : : 9000 9000 9000  c : a : b = 4500 : 3000 : 2250 = 450 : 300 : 225  c : a : b = 30 : 20 : 15

 a = 20; b = 15; c = 30 (Also 20  15  30 = 9000)

 The shortest side is 15 cm.

23. (A) 24. (D)

25. (C)

3

512  3 3.375 = 8  1.5 = 12

In option (C), friction is needed to balance the ladder, so that it will not slip.

Since diagonals of a square are equal and bisect at right angles, triangle AOB is an isosceles right angled triangle. 2 x

3 y

5  = 5 

In option (D), friction is needed to create fire (heat) to strike and light a match stick.

(Since (am)n = amn.)

In option (B), friction is not needed to cause a ball to bounce.

 52x = 53y  2x = 3y [When bases are equal, powers can be equated.]



x 3 = y 2

33. (C)

Persistence of vision is a phenomenon where the brain continues to sense the image even after the object has been removed. This lasts for 1/16th of a second.

34. (A)

There are several effects of force. It can change the shape, speed and direction of motion of an object.

35. (C)

In a voltaic cell, chemical energy is converted to electrical energy.

36. (C)

The loudness of sound depends on the amplitude of vibration. The loudness or softness of a sound produced depends on the amplitude. Larger the amplitude, louder the sound, smaller the amplitude, softer is the sound produced.

 x:y=3:2

Physics 26. (C)

The inner layer of the eye called the choroid is black. This prevents internal reflections of light inside the human eye.

27. (B)

In a longitudinal wave like sound wave, the distance between two consecutive rarefactions or between two consecutive compressions is called wavelength.

28. (B)

Friction opposes motion, so it causes wear and tear to surfaces in contact.

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37. (A)

38. (B)

39. (A)

40. (B)

least distance and hence, the greatest friction.

The outer layer of the earth, on which we live is called the crust. The thickest part of the earth’s crust is the continent. Material Y becomes negatively charged after it is rubbed with fur, because the electrons from the fur get transferred to the material. Thus, the material gains electrons that far out number the protons in it and develops a negative charge.

44. (C)

Venus takes maximum time of 243 days for one rotation around its own axis.

45. (C)

The electric field direction is the direction of the force acting on a positive test charge. The positive charge object repels the positive point charge and the negative charge object attracts the positive point charge.

Speed of sound in air is approximately 330 m s –1. Speed of sound in water is approximately 1500 m s–1. Speed of sound in steel is approximately 5000 m s –1.

+

An LED has two leads. One lead is slightly longer than the other. The longer lead is always connected to a positive terminal of the battery while the shorter lead is always connected to a negative terminal of the battery. In circuit (B) switch is present and is in its ON position. Only this makes the LED glow.

42. (D)

Nocturnal animal like owl needs more light to see at night. The large cornea and pupil allows more light to enter into its eyes. They also have retina with large number of rods and only a few cones.

43. (C)

–

47. (D)

Ultrasound is used in all the given three applications.

48. (D)

When an object is placed in front a plane mirror, it forms an image which is virtual, erect and of the same size as the object and laterally inverted.

49. (D)

Zinc can be better than tin for protecting iron from rusting. Z inc being highly electropositive can prevent rusting even when the layer is broken.

50. (A)

Sharpening the knife makes use of frictional force exerted on the knife edge to remove parts of the material through wear and tear.

Chemistry 51. (C)

Petroleum is a mixture of various constituents such as petroleum gas (LPG), petrol, kerosene, diesel, lubricating oil, paraffin wax etc. Various constituents or fractions of petroleum are separated in a petroleum refinery.

52. (D)

Carbon monoxide which binds to the haemoglobin prevents oxygen from binding. This causes reduction in the amount of oxygen circulated in the blood which in turn causes inadequate amount of oxygen distributed to the body. Carbon monoxide is poisonous, however it is difficult for us to detect due to its colourless, odourless and tasteless property.

1 2 3

Distance

a ract

When the brakes of a bike are on, its wheels cannot rotate. They will simply skid. Then rolling friction will be converted into skidding friction which is comparatively large. Hence, it becomes difficult to move the bike.

friction

The gravitational force and frictional force are acting against the motion of the ball in this case. Both play a role in decreasing the speed of the ball until it eventually stops moving.

+

46. (A)

41. (D) gravity

repel

4 Time

The one with the greatest amount of friction will be the hardest to move. At any time, the distance travelled by the system is indicated by the four points in the graph. Graph number 4 shows the

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53. (B)

Ammonia gas reacts with HCl to form ammonium chloride. Sodium hydroxide is neutralised by HCl to form salt and water. Silver is too unreactive to react with HCl.

ii) Liquid fuel like kerosene oil is a petroleum product that is used in stoves, lamps etc. has hydrocarbon. This fuel vapourises on burning. iii) Gaseous fuel like LPG is also a petroleum product made up of methane along with butane and propane in small proportions.

Fe + 2HCl  FeCl 2 + H 2 54. (A)

Accumulating metals and transporting them from different collection centers to recycling plants incur cost.

55. (D)

CNG is a cleaner and a less polluting fuel.

56. (A)

When there is a sufficient supply of oxygen, the substances burn completely producing a non-luminous or blue flame. Insufficient supply of oxygen produces a yellow flame due to the glowing of unburnt carbon atoms.

57. (D)

Tincture of iodine is used on wounds as an antiseptic.

58. (B)

Rayon is obtained from natural source and yet it is synthetic.

59. (B)

Coal tar is a mixture of about 200 substances.

60. (A)

61. (C)

As mentioned above, the constituents in solid, liquid and gaseous fuels are not the same, hence the flame produced by a fuel depends upon its chemical composition.

Incomplete combustion occurs when there is insufficient oxygen as the fuel is burnt. The amount of oxygen is not enough to fully oxidise the fuel and would result in the formation of carbon monoxide. Mg(magnesium) is more reactive than Fe(iron). When connected, Mg will react with O2 preferentially.

62. (D)

Since wool is made from fleece/hair of sheep, it gives the smell of burning hair.

63. (C)

The type of fuel involved in the combustion determines the type of flame (colour and temperature of a flame varies with the chemical composition of the fuel).

64. (D)

Hydrogen is not a fossil fuel.

65. (C)

The reaction of aluminium with oxygen to form aluminium oxide is a chemical change which requires energy to occur. It is an irreversible change. The layer of aluminium oxide protects the underlying aluminium from coming into contact with air. This prevents further oxidation and keeps the aluminium shiny.

66. (B)

Teflon is thermally most stable and chemically inert.

67. (A)

A burning substance will be extinguished if the temperature falls below its ignition temperature.

68. (A)

Solid fuels leave more smoke and ash on burning because they contain a large number of impurities.

69. (B)

Bakelite is a poor conductor of heat and electricity. It is used for making electrical switches, handles of kettles, pans, lamp holders, pins, plugs etc.

70. (D)

Non-metals have low densities, low melting points and are poor conductors of electricity.

71. (B)

Unwanted plants are called weeds.

72. (B)

Thyroid gland plays a key role in metamorphosis in frog.

73. (C)

Migration is the movement of an animal species from its own habitat to other habitat for a particular period.

74. (D)

Plastids are pigmented cell organelles.

75. (A)

Rearing of fishes is called pisciculture.

76. (A)

Cycas is a green plant that belong to gymnosperms. It contains chloroplast.

Biology

All fuels, solid, liquid and gaseous are carbon rich compounds. Carbon is the base fuel. In addition fuels specially obtained from petroleum are rich in hydrogen. Petroleum fuels are hydrocarbons. i) Solid fuel like coal has varied percentage of carbon in anthracite, bituminous and lignite respectively along with other substances like hydrogen, oxygen, nitrogen and sulphur.

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77. (A)

Red data book contain list of endangered species of plants and animals.

83. (C)

In the given figure W - virus, X - fungus and Y - protozoan.

78. (A)

Chromosomes information.

genetic

84. (A)

Options A is euglena which can prepare its own food.

79. (D)

Fertilisation is external in fish and amphibians.

85. (B)

Energy flow in an ecosystem is unidirectional.

80. (D)

Reduce the dependency on human and animal labour and get the job done faster.

86. (D)

One ova is released at a time in female human beings.

81. (C)

Rhizobium bacteria are present in root nodules.

87. (D)

Adrenal gland in mammals is located on top of kidney.

82. (A)

A nerve cell is the longest cell in the human body.

88. (B)

Viruses cause common cold.

89. (A)

Echidna is an oviparous animals.

90. (B)

The genetic material found in a sperm is 22 + Y.

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