Physics

SUMMER WORKSHOP (IJSO) Daily Practice Problem Sheet Subject : Physics 1.

Topic : Electricity

DPP No. : 1

Three equal charges (each Q coulomb) are placed at the three corners of an equilateral triangle. What will be the nature and magnitude of charge q placed at the centre of the triangle so that the system will be in equilibrium : (A) –Q/ 3

(B) –Q/4

(C) – Q

(D) none of these

2.

If we increases the current drawn from the battery then the potential difference across the battery will : (A) Increase (B) decrease (C) remain same (D) Noen fo these

3.

The equivalent resistance between A and B will be (in )

(A) 2/7 4.

(B) 8

(C) 4/3

(D) 7/3

In the given network of four resistances, the equivalent resistance is

(A) 20 

(B) 5.4 

(C) 12 

(D) 4.5 

5.

Find the equivalent resistance of the circuit between the terminals A and B .

6.

(A) 7  (B) 12  (C) 9  The equivalent resistance between the points A and B is :

(A)

36 7



(B) 10 

(C)

85 7

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

(D) 6 

(D) none of these Page # 1

7.

The equivalent resistance between the points A and B is

(A) 8.

5R 9

(B)

2R 3

(C) R

(D) None of these

Find the error in the voltmeter connected in the circuit shown in figure . V a

b 8K

(A) 0.27 V

(B) 0.25 V

4V

(C) 0.29 V

(D) 0.32 V

9.

An electrical bulb rated for 500 W at 100 V is used in a circuit having a 200V supply. Calculate the resistance that one must put in series with the bulb, so that the bulb delivers 500 W. (A) 70 (B) 40 (C) 50 (D) 20

10.

A copper wire is stretched to decrease its radius by 0.15%, then the percentage increase in resistance is approximately : (A) 0.15% (B) 0.40% (C) 0.60% (D) 0.90%

11.

40W, 60W, 100W and 500W bulbs working on 220 Volt AC are conected in the electric circuit in such a way that same current flows through each bulb. The bulb having maximum resistance is : (A) 500W (B) 100W (C) 60W (D) 40W

12.

A circuit has fuse of 5A. What is the maximum number of 100W (220 V) bulb that can be connected in parallel to each other in the circuit ? (A) 5 (B) 7 (C) 9 (D) 11

13.

Conductivity of superconductor is : (A) infinite (B) very large

(C) very small

(D) zero

14.

Two charges of +1 C & + 5 C are placed 4 cm apart, the ratio of the force exerted by both charges on each other will be (A) 1 : 1 (B) 1 : 5 (C) 5 : 1 (D) 25 : 1

15.

A body has 80 microcoulomb of charge. Number of additional electrons on it will be : (A) 8 x 10–5 (B) 80 x 1015 (C) 5 x 1014 (D) 1.28 x 10–17

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SUMMER WORKSHOP (IJSO) Daily Practice Problem Sheet Subject : Physics

Topic : Light

DPP No. : 2

1.

What should be the minimum height of plane mirror required to view complete image of a wall of height H behind you : (A) H/2 (B) H/3 (C) H/4 (D) H

2.

In a room lighted by an electric bulb, it is found that the shadow of the ceiling fan hung in the centre is falling on a wall opposite to the door. What can you say about the position of the bulb ? (A) On the wall having the door (B) On the wall facing the door (C) On the wall on your right as you enter the room (D) On the wall on your left as you enter the room

3.

A plane mirror is rotated by an angle  about the plane perpendicular to the plane of incidence. The reflected ray will turn by an angle : (A)  (B) 2 (C) 3 (D) None of these

4.

Two parallel plane mirrors A and B are placed at a separation 10 cm as shown in figure. A ray incident on the corner of mirror B at an angle of incidence 45º. Find the number of times this rays is reflected from mirror A :

(A) 4 5.

(C) 6

(D) 7

Find the angle at which reflected ray will strike the upper mirror.

(A) 10º 6.

(B) 5

(B) 0º

(C) 5 º

(D) 20º

As per New Cartesian Sign Convention : (A) Focal length of concave mirror is positive and that of convex mirror is negative (B) Focal length of both, convex and concave mirror is positive (C) Focal length of both, convex and concave mirror is negative (D) Focal length of concave mirror is negative and that of convex mirror is positive

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7.

8.

9.

How far a concave mirror of focal length 20 cm should be kept from over face if we want to see exact inverted image of our face ? (A) 30 cm (B) 40 cm (C) 50 cm (D) 60 cm Focal length of a convex mirror is 10 cm. An object is placed at 10 cm from the mirror. Find the position of the image. (A) 5 cm (B) 15 cm (C) 18 cm (D) 20 cm Which of the following correctly depicts the graphical variation in case of a spherical mirror ?

(A)

10.

11.

(B)

(C)

(D)

In normal incidence from plane mirror what will be angle of deviation : (A) 0º (B) 90º (C) 180º

(D) 360º

The linear magnification for a mirror is the ratio of the size of the image to the size of the object, and is denoted by m. Then m is equal to (symbols have their usual meanings) : (A)

uf uf

(B)

uf uf

(C)

f uf

(D) none of these

12.

The angle beyond which when a ray is incident, it is completely reflected back is called : (A) angle of deviation (B) critical angle (C) incident angle (D) angle of inversion

13.

Which of the following conditions are necessary for total internal reflection to take place at the boundary of two optical media ? 1. Light is passing from optically denser medium to optically rarer medium. 2. Light is passing from optically rarer medium to optically denser medium. 3. Angle of incidence is greater than the critical angle. 4. Angle of incidence is less than the critical angle. (A) 1 and 3 only (B) 2 and 4 only (C) 3 and 4 only (D) 1 and 4 only

14.

For total internal reflection, rays of light must go from : (A) Rarer to denser medium (B) Rarer to rarer medium (C) Denser to rarer medium (D) Denser to denser medium

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Page #2

SUMMER WORKSHOP (IJSO) Daily Practice Problem Sheet Subject : Physics 1.

(B) 2 Mg

(C) Mg + F

(D) none of these

Two blocks of mass m each is connected with the string which passes over fixed pulley, as shown in figure. The force exerted by the string on the pulley P is :

(A) mg 3.

DPP No. : 3

Two blocks, each of mass M, are connected by a massless string, which passes over a smooth massless  pulley. Forces F act on the blocks as shown. The tension in the string is :

(A) Mg 2.

Topic : Newton’s law of motion

(B) 2 mg

(C) 2 mg

(D) 4 mg

One end of a massless rope, which passes over a massless and frictionless pulley P is tied to a hook C while the other end is free. Maximum tension that rope can bear is 360 N, with what minimum safe acceleration (in m/s2) can a monkey of 60 kg move down on the rope : P

C

4.

(A) 16 (B) 6 (C) 4 (D) 8 Which figure represents the correct F.B.D. of rod of mass m as shown in figure :

(A)

(B)

(C)

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(D) None of these Page # 1

5.

Two persons are holding a rope of negligible weight tightly at its ends so that it is horizontal. A 15 kg weight is attached to the rope at the mid point which now no longer remains horizontal. The minimum tension required to completely straighten the rope is : 15 kg 2 (D) Infinitely large (or not possible)

(A) 15 kg

(B)

(C) 5 kg 6.

In the figure, the blocks A, B and C of mass each have acceleration a1 , a2 and a3 respectively . F1 and F2 are external forces of magnitudes 2 mg and mg respectively then which of the following relations is correct :

(A) a1 = a2 = a3 7.

(D) a1 > a2 , a2= a3

(B) 20 N

(C) 5 N

(D) Zero

A mass M is suspended by a rope from a rigid support at A as shown in figure. Another rope is tied at the end B, and it is pulled horizontally with a force F. If the rope AB makes an angle  with the vertical in equilibrium,then the tension in the string AB is :

(A) F sin  9.

(C) a1 = a2 , a2 > a3

In the given figure. What is the reading of the spring balance:

(A) 10 N 8.

(B) a1 > a2 > a3

(B) F /sin 

(C) F cos 

(D) F / cos 

In the system shown in the figure, the acceleration of the 1kg mass and the tension in the string connecting between A and B is :

(A)

g 8g downward, 4 7

(B)

g g upward, 4 7

(C)

g 6 g downward, g (D) upward, g 7 7 2

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10.

A body of mass 8 kg is hanging from another body of mass 12 kg. The combination is being pulled by a string with an acceleration of 2.2 m s–2. The tension T1 and T2 will be respectively :(Use g =9.8 m/s2)

(A) 200 N, 80 N 11.

(B) 220 N, 90 N

M2 (sin ) g M1  M2  M2 sin   M1 sin    g (C)  M1  M2  

(B)

M1g(sin  ) M1  M2

(D) Zero

Three masses of 1 kg, 6 kg and 3 kg are connected to each other by threads and are placed on table as shown in figure. What is the acceleration with which the system is moving ? Take g = 10 m s–2:

(A) Zero 13.

(D) 260 N, 96 N

Two masses M1 and M2 are attached to the ends of a light string which passes over a massless pulley attached to the top of a double inclined smooth plane of angles of inclination  and . If M2 > M1 then the acceleration of block M2 down the inclined will be :

(A)

12.

(C) 240 N, 96 N

(B) 1 ms–2

(C) 2 m s–2

(D) 3 m s–2

The pulley arrangements shown in figure are identical the mass of the rope being negligible. In case I, the mass m is lifted by attaching a mass 2m to the other end of the rope. In case II, the mass m is lifted by pulling the other end of the rope with a constant downward force F= 2 mg, where g is acceleration due to gravity. The acceleration of mass in case I is :

(A) Zero (C) Less than that in case II

(B) More than that in case II (D) Equal to that in case II

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14.

A 50 kg person stands on a 25 kg platform. He pulls massless rope which is attached to the platform via the frictionless, massless pulleys as shown in the figure. The platform moves upwards at a steady velocity if the force with which the person pulls the rope is :

(A) 500 N 15.

(B) 250 N

(C) 25 N

(D) 50 N

Figure shows four blocks that are being pulled along a smooth horizontal surface. The mssses of the blocks and tension in one cord are given. The pulling force F is : F 30N 60º

(A) 50 N

(B) 100 N

4kg

3kg

2kg

(C) 125 N

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1kg

(D) 200 N

Page # 4

SUMMER WORKSHOP (IJSO) Daily Practice Problem Sheet Subject : Physics

Topic : Projectile motion

DPP No. : 4

1.

The horizontal and vertical components of the velocity of a projectile are 10 m/s and 20 m/s, respectively . The horizontal range of the projectile will be : [g =10m/s2] (A) 5m (B) 10m (C) 20m (D) 40m

2.

A large number of bullets are fired in all directions with same speed u. What is the maximum area on the ground on which these bullets will spread ? (A) 

u2 g

(B) 

u4 g2

2 (C) 

u4 g2

2 (D) 

u2 g2

3.

A projectile fired with initial velocity u at some angle has a range R. If the initial velocity be doubled at the same angle of projection, then the range will be : (A) 2R (B) R/2 (C) R (D) 4R

4.

In the motion of a projectile freely under gravity, its : (A) Total energy is conserved (B) Momentum is conserved (C) Energy and momentum both are conserved (D) None is conserved

5.

At the top of the trajectory of a projectile , the directions of its velocity and acceleration are : (A) Perpendicular to each other (B) Parallel to each other (C) Inclined to each other at an angle of 45º (D) Antiparallel to each other

6.

Galileo writes that for angles of projection of a projectile at angles (45 +) and (45 –) ,their horizontal ranges described by the projectile are in the ratio of : (if   45) (A) 2 :1

7.

(B) 1 : 2

(C) 1 : 1

(D) 2 : 3

A projectile thrown with a speed  at an angle  has a range R on the surface of earth . For same  and , its range on the surface of moon will be : (A) R/6

(B) 6R

(C) R/36

(D) 36R

8.

A stone is just released from the window of a train moving along a horizontal straight track. The stone will hit the ground following : (A) Straight path (B) Circular path (C) Parabolic path (D) Hyperbolic path

9.

A bullet is dropped from the same height when another bullet is fired horizontally. They will hit the ground : (A) One after the other (B) Simultaneously (C) Depends on the observer (D) None of the above

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10.





you throw a ball with a launch velocity of v = 3ˆi  4ˆj m/s towards a wall, where it hits at height h1.





Suppose that the launch velocity is v  5ˆi  4ˆj m/s. If h2 is corresponding height(h > h1 & h2), then

h

(A) h2 = h1 11.

(B)h2 < h1

(C) h2 > h1

(D) unanswerable

A boy throws a ball with a velocity u at an angle with the horizontal. At the same instant he starts running with uniform velocity to catch the ball before it hits the ground. To achieve this he should run with a velocity of: (A) u cos

 u sin

(C) u tan

(D) u2 tan 

12.

The height y and the distance x along the horizontal plane, of a projectile on a certain planet [with surrounding atmosphere] are given by y =[5t –8t2] metre and x =12t metre where t is the time in second. The velocity with which the projectile is projected, is : (A) 5 m/s (B) 12m/s (C) 13 m/s (D) not obtainable from the data

13.

A particle is projected from the ground with a velocity of 25m/s. After 2 second, it just clears a wall 5m height. Then the angle of projection of particle is [g =10 m/s2]: (A) 30º (B) 45º (C) 60º (D) 75º

14.

A cricket ball is hit at angle 60º with the horizontal with kinetic energy k. What will be the kinetic energy at the highest point of its trajectory ? (A) zero

15.

(B)

k 4

(C)

k 2

(D)

3k 4

What determines the nature of the path followed by the particle ? (A) speed (B) velocity (C) acceleration (D) initial velocity and acceleration

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