DAILY PRACTICE PROBLE FOR NSO for Class VIII

DAILY PRACTICE PROBLEMS FOR NSO PHYSICS

DPP : 01

Class – VIII

TOPIC : FORCE 1.

On applying a force on a moving object, in the same direction in which it was moving, we find that (A) the distance covered by it in a given interval of time increases. (B) the distance covered by it in a given interval of time decreases. (C) moving object changes its direction. (D) it keeps on moving with the same speed as earlier.

2.

Porters find it easy to carry load with wider area on the head because the pressure is (A) increased. (B) reduced. (C) greater than before. (D) zero.

3.

The force applied to take out the paste from a toothpaste tube is an example of (A) muscular force. (B) magnetic force. (C) gravitational force. (D) electrostatic force.

4.

The principle of barometer was first developed by the scientist (A) Torricelli. (B) Pascal. (C) Archimedes. (D) Newton.

5.

A boy is running towards a plane mirror with speed 20 ms-1. As seen by the boy, the image moves with the speed of (A) 20 ms-1 towards him. (B) 40 ms-1 towards him. -1 (C) 60 ms towards him. (D) 80 ms-1 towards him.

6.

When a person is suffering from cataract, the affected part of the eye is (A) iris. (B) cornea. (C) ciliary muscle. (D) eye lens.

7.

A 1000 kg truck moving with a speed of 20 m/s is brought to rest within a distance of 50 m by applying brakes that provide uniform retardation. (A) The retardation = – 2 m s-2 (B) The retardation = – 4 m s-2 (C) Retarding force= – 4000 N (D) Retarding force= – 8000 N

8.

When food packets are dropped from an aircraft, (A) they hit the ground vertically below the aircraft. (B) they fall on the ground behind the aircraft’s position. (C) they fall on the ground further ahead. (D) they can fall anywhere on the ground.

9.

A ball of mass 0.5 kg moving with a velocity of 2 m/sec strikes a wall normally and bounces back with the same speed. If the time of contact between the ball and the wall is one millisecond, the average force exerted by the wall on the ball is (A) 2000 N. (B) 1000 N. (C) 500 N. (D) 125 N.

10.

When a horse pulls a wagon, the force that causes the horse to move forward is the force, (A) the horse exerts on the wagon. (B) the wagon exerts on the horse. (C) the horse exerts on the ground. (D) the ground exerts on the horse. (1 Mark)

11.

If force acting on 2 bodies of masses 3 kg and 18 kg is same, then find the ratio of the acceleration produced in them. (A) 6 : 1 (B) 1 : 6 (C) 2 : 6 (D) 6 : 2

12.

Sita attaches a weight of 2W with the wooden block placed on the surface of the table through the thread passing over the pulley. The force exerted on the wooden block will be equal to 2W if

(A) there is no movement of the block. (B) there is no friction in the pulley. (C) there is no friction in the pulley and there is no frictional force between the surface of the table and the surface of the block. (D) there is no frictional force between the surface of the table and the surface of the block. 13.

14.

Which of the following force is not electromagnetic in nature ? (A) Tension in a string

(B) Weight of a body

(C) Elastic force in spring

(D) Force of friction

A horizontal force of 100 N acts on a body which is at rest. What is the force of friction between the body and the floor ? (A) 50 N

15.

(B) 100 N

(C) 150 N

(D) 200 N

Gravels are dropped on to a conveyor belt at the rate of 0.5 kgs–1. The extra force in newton required to keep the belt moving at 2 ms–1 is : (A) 1 (B) 2 (C) 4 (D) 5

DAILY PRACTICE PROBLEMS FOR NSO PHYSICS

DPP : 02

Class – VIII

TOPIC : SOUND & LIGHT 1.

A broadcasting station transmits waves of frequency 71 × 104 Hz with a speed of 3 × 108 m/s. The wavelength of the wave is : (A) 418.8m (B) 324.6 m (C) 208.4 m (D*) 422.5 m

2.

As compared to men, the voice of a women have higher (A) loudness and amplitude. (B) loudness and pitch. (C) frequency and pitch. (D) frequency and amplitude.

3.

As the distance between the source of sound and the observer increases, the intensity of sound (A) decreases. (B) increases. (C) remains unchanged. (D) first decreases and then increases.

4.

In a tabla, striking the skin harder or stretching it tighter, the loudness and pitch (A) increases. (B) decreases. (C) has no effect. (D) becomes feeble.

5.

The wavelength of visible light is in the range of (A) 4 × 10-7 m to 8 × 10-7 m (B) 4 × 107 m to 8 × 107 m (C) 4 × 103 m to 8 × 103 m (D) 2 × 10-3 m to 3 × 10-4 m

6.

The magnification produced by a convex mirror will be (A) positive and greater than unity. (B) negative and less than unity. (C) positive and less than unity. (D) zero. (C) positive and less than unity.

7.

Mirrors used in vehicle headlights are: (A) Concave mirrors (C) Plane mirrors

8.

Stars twinkle due to atmospheric (A) reflection of light. (C) diffraction of light. (D) lateral inversion of light.

(B) Convex mirrors (D) Any spherical mirror

(B) refraction of light.

9.

The three primary colours of light are (A) red, blue and green. (B) red, yellow and blue. (C) red, white and blue. (D) violet, green and red.

10.

Light is scattered by the atmospheric particles. This phenomenon results in (A) blue appearance of sky. (B) twinkling of star. (C) visibility of sun before the actual sunrise. (D) Formation of rainbow.

11.

Radha finds that when she enters a dark room from the well-lit living room, she is unable to see things for some time. This is due to (A) improper functioning of cornea. (B) contraction of lens. (C) improper functioning of retina. (D) contraction of pupil.

12.

A wave of frequency 250 Hz is produced in an iron rod in which its velocity is 4800 m/s. Now, it passes into air in which velocity is 332 m/s. Its wavelength in iron will be (A) 4800 × (332/250) m. (B) (4800/250) m. (C) (332/250) m. (D) 4800 / (332×250) m.

13.

The types of waves, which are produced when a slinky is plucked as shown below, are

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

transverse and longitudinal waves, respectively. longitudinal and transverse waves, respectively. transverse wave only. longitudinal wave only.

14.

Suppose a ship sends a pulse of ultrasound and receives an echo 0.2 seconds later. If the speed of sound in water is 1000 m/s, the depth of the sea is (A) 100 m. (B) 200 m. (C) 1000 m. (D) 2000m.

15.

In case of reflection of sound a graph drawn between the angles of incidence and the angles of reflection will be (A) a straight line. (B) a parabola. (C) a circle. (D) a random curve.