Physics Model Question Paper 14: (For Class 11 and 12 and Pre-Medical/Engineering Entrance)

1.

A charged cloud system produces an electric field in the air near the earth's surface. A particle of charge -2 ´ 10^–9 C is acted on by a downward electrostatic force of 3 ´ 10^–6 N when placed in this field. The gravitational and electrostatic force, respectively, exerted on a proton placed in this field are

(A) 1.64 ´ 10^–26 N, 2.4 ´ 10^–16 N

(B) 1.64 ´ 10^–26 N, 1.5 ´ 10³ N

(C) 1.56 ´ 10^–18 N, 2.4 ´ 10^–16 N

(D) 1.5 ´ 10³ N, 2.4 ´ 10^–16 N

Answer: (A)

2.

A conductor wire having 10²⁹ free electrons/m³ carries a current of 20 A. If the cross-section of the wire is 1 mm², then the drift velocity of electrons will be ______.

(A) 6.25 ´ 10^–3 ms^–1

(B) 1.25 ´ 10^–5 ms^–1

(C) 1.25 ´ 10^–3 ms^–1

(D) 1.25 ´ 10^–4 ms^–1

Answer: (C)

3.

A cricket ball of mass 0.25 kg with speed 10 m/s collides with a bat and returns with same speed within 0.01 S. The force acted on bat is

(A) 25 N

(B) 50 N

(C) 250 N

(D) 500 N

Answer: (D)

4.

A cubical vessel of height 1 m is full of water. What is the amount of work done in pumping water out of the vessel? (Take g =10 m s^–2)

(A) 1250 J

(B) 5000 J

(C) 1000 J

(D) 2500 J

Answer: (B)

5.

A current flows in a conductor from east to west. The direction of the magnetic Held at a point above the conductor is _______.

(A) towards north

(B) towards south

(C) towards east

(D) towards west

Answer: (A)

6.

A current of  A produces a deflection of 60° in a tangent galvanometer. The reduction factor is

(A) A

(B) 2A

(C) A

(D) A

Answer: (C)

7.

A current of 2 A flows through a 2 W resistor when connected across a battery. The same battery supplies a current of 0.5 A when connected across a 9 Wresistor. The internal resistance of the battery is

(A) 1 W

(B) 0.5 W

(C) 1/3 W

(D) 1/4 W

Answer: (C)

8.

A diver at a depth of 12 m in watersees the sky in a cone of semi vertical angle:

(A) sin^-1

(B) tan^-1

(C) sin^-1

(D) 90°

Answer: (C)

9.

A In Young's double slit experiment if monochromatic light used is replaced by white light, then _______.

(A) all bright fringes become white.

(B) all bright fringes have colours between violet and red.

(C) no fringes are observed.

(D) only central fringe is white, all other fringes are coloured.

Answer: (D)

10.

A man, standing between two cliffs, claps his hands and starts hearing a series of echoes at intervals of one second. If the speed of sound in air is 340 ms^-1, the distance between the cliffs is _______.

(A) 340 m

(B) 1620 m

(C) 680 m

(D) 1700 m

Answer: (A)

11.

A material has Poisson's ratio 0.50. If a uniform rod of it suffers a longitudinal strain of 2 × 10^–3, then the percentage change in volume is

(A) 0.6

(B) 0.4

(C) 0.2

(D) zero

Answer: (D)

12.

A parallel beam of light of wavelength 6000  gets diffracted by a single slit of width 0.3 mm. The angular position of the first minima of diffracted light is ______.

(A) 6 ´ 10^–3 rad

(B) 1.8 ´ 10^–3 rad

(C) 3 ´ 10^–3 rad

(D) 2 ´ 10^–3 rad

Answer: (D)

13.

A particle executing a simple harmonic motion has a period of 6 sec. The time taken by the particle to move from the mean position to half the amplitude, starting from the mean position is

(A)  sec

(B)  sec

(C)  sec

(D)  sec

Answer: (C)

14.

A particle is moving with a constant speed n in a circle. What is the magnitude of average velocity after half rotation?

(A) 2n

(B) 2

(C)

(D)

Answer: (B)

15.

A particle moves in a circle of radius 5 cm with constant speed and time period 0.2 p s. The acceleration of the particle is

(A) 5 m/s    

(B) 15 m/s²

(C) 25 m/s²

(D) 36 m/s²

Answer: (A)