Question BankFlame Institute

PRACTICE TEST

Buna -S rubber is which of the following of 1-3 butadiene and styrene

a. Polymers b. Copolymer c. Addition d. Condensation polymer Ans. b (30)

23. If the length of a wire is reduced to half, then it can hold the ……… load

(a) Half (b) Same (c) Double …

22. A and B are two wires. The radius of A is twice that of B. They are stretched by the some load. Then the stress on B is

(a) Equal to that on A (b) Four times that on A (c) Two times that on A (d) Half that on A Explanation-B (24)

104. A symmetrical body of mass M and radius R is rolling without slipping on a horizontal surface with linear speed v. Then its angular speed is

(a) v/R (b) Continuously increasing (c) Dependent on mass (d) Independent of radius (R) Ans. a (62)

100. A solid sphere is moving on a horizontal plane. Ratio of its transitional Kinetic energy and rotational energy is

(a) 1/5 (b) 5/2 (c) 3/5 (d) 5/7 Ans. b (6)

Acceleration due to gravity ‘g’ for a body of mass ‘m’ on earth’s surface is proportional to (Radius of earth=R, mass of earth=M)

(a) GM/R2 (b) m0 (c) mM (d) 1/R3/2 …

78. An equilateral triangle ABC formed from a uniform wire has two small identical beads initially located at A. The triangle is set rotating about the vertical axis AO. Then the beads are released from rest simultaneously and allowed to slide down, one along AB and the other along AC as shown. Neglecting frictional effects, the quantities that are conserved as the beads slide down, are

(a) Angular velocity and total energy (kinetic and potential) (b) Total angular momentum and total energy (c) Angular velocity and moment of inertia about the axis of rotation (d) Total angular momentum and moment of inertia about …

76.

Two rigid bodies A and B rotate with rotational kinetic energies EA and EB respectively. The moments of inertia of A and B about the axis of rotation are IA and IB respectively. If IA = IB /4 and EA …

61. From a uniform wire, two circular loops are made (i) P of radius r and (ii) Q of radius nr. If the moment of inertia of Q about an axis passing through its centre and perpendicular to its plane is 8 times that of P about a similar axis, the value of n is (diameter of the wire is very much smaller than r or nr)

(a) 8 (b) 6 (c) 4 (d) 2 Ans. d (6)

24. Assertion : A body subjected to three concurrent forces cannot be in equilibrium. Reason : If large number of concurrent forces acting on the same point, then the point will be in equilibrium, if sum of all the forces is equal to zero.

(a) If both assertion and reason are true and the reason is the correct explanation of the assertion. (b) If both assertion and reason are true but reason is not the correct explanation of the assertion. (c) If assertion is …

22. Assertion : A reference frame attached to earth is an inertial frame of reference. Reason : The reference frame which has zero acceleration is called a non inertial frame of reference.

A geostationary satellite

(a) Revolves about the polar axis (b) Has a time period less than that of the near earth satellite (c) Moves faster than a near earth satellite (d) Is stationary in the space Answer: a (12)

The pigment phycoerythrin is characteristic of

(a) Green algae (b) Brown algae (c) Red algae (d) Blue green algae Ans. c (8)

Two identical solid copper spheres of radius R placed in contact with each other. The gravitational attracton between them is proportional to

(a) R2 (b) R–2 (c) R4 (d) R–4 Answer: c (17)

Which of the following statements about the gravitational constant is true

(a) It is a force (b) It has no unit (c) It has same value in all systems of units (d) It depends on the value of the masses (e) It does not depend on the nature of the …

54. Moment of inertia of a sphere of mass M and radius R is I. Keeping constant if a graph is plotted between I and R, then its form would be

Ans. d (21)

46. A wheel of mass 10 kg has a moment of inertia of 160 kg–m2 about its own axis, the radius of gyration will be

(a) 10 m (b) 8 m (c) 6 m (d) 4 m Ans. d (42)

Assertion : A light body and heavy body have same momentum. Then they also have same kinetic energy. Reason : Kinetic energy does not depend on mass of the body.

27. When a ceiling fan is switched off, its angular velocity falls to half while it makes 36 rotations. How many more rotations will it make before coming to rest (Assume uniform angular retardation)

(a) 36 (b) 24 (c) 18 (d) 12 Ans. d (16)

23. The planes of two rigid discs are perpendicular to each other. They are rotating about their axes. If their angular velocities are 3 rad/sec and 4 rad/sec respectively, then the resultant angular velocity of the system would be

(a) 1 rad/sec (b) 7 rad/sec (c) 5 rad/sec (d) √12 rad/sec Ans. c (552)

7. A 100 g iron ball having velocity 10 m/s collides with a wall at an angle 30° and rebounds with the same angle. If the period of contact between the ball and wall is 0.1 second, then the force experienced by the wall is

(a) 10 N (b) 100 N (c) 1.0 N (d) 0.1 N answer : a (6)

6. If a force of 250 N act on body, the momentum acquired is 125 kg-m/s. What is the period for which force acts on the body

(a) 0.5 sec (b) 0.2 sec (c) 0.4 sec (d) 0.25 sec answer : a (29)

5. A wagon weighing 1000 kg is moving with a velocity 50km/h on smooth horizontal rails. A mass of 250 kg is dropped into it. The velocity with which it moves now is

(a) 2.5 km/hour (b) 20 km/hour (c) 40 km/hour (d) 50 km/hour answer : c (4)

4. In which of the following cases forces may not be required to keep the

(a) Particle going in a circle (b) Particle going along a straight line (c) The momentum of the particle constant (d) Acceleration of the particle constant ANSWER: c (9)