Competitive Exams: Physics MCQs (Practice-Test 17 of 35)

  1. Match List I with List II and select the correct answer using the codes given below the lists:

    List-I (Physical Quantity) List-II (Dimension)
    1. Angular momentum

    2. Torque

    3. Surface tension

    4. Coefficient of viscosity

    1. ML-1 T − 1

    2. MT-2

    3. ML2 T − 1

    4. ML1 T − 2

    • A
    • B
    • C
    • D
      • 4
      • 3
      • 2
      • 1
      • 3
      • 4
      • 2
      • 1
      • 1
      • 4
      • 2
      • 3
      • 3
      • 1
      • 4
      • 2
  2. The dimension of centripetal force is

    1. L2/T2

    2. L2/T

    3. L/T2

    4. 1/T2

  3. A wheel of radius 1 metre rolls forward half a revolution oh a horizontal ground. The magnitude of the displacement of the point of the wheel initially in contact with the ground is

    1. 2 p

    2. V2p

    3. pV2 + 4

    4. p

  4. Two forces each of magnitude 2N, act at an angle of 600. The magnitude of the resultant force is

    1. V1.1 Newton

    2. V4 Newton

    3. V12 Newton

    4. V14.9 Newton

  5. A particle moves in the direction of east for 2 s with a velocity of 15 m/s. Then it moves towards north for 8 s with a velocity of 5 m/s. The average velocity of the particle is

    1. 1 m/s

    2. 5 m/s

    3. 7 m/s

    4. 10 m/s

  6. For an electron moving in an elliptical orbit with the nucleus at the focus of the ellipse, the torque on the electron with respect to the nucleus

    1. is zero at all times

    2. is constant but not zero

    3. varies with position

    4. cannot be defined

  7. A body of mass 2 kg is moving under the influence or a central force whose potential energy is given by U (r) = 2r3 Joule. If the body is moving in a circular orbit of 5 m, its energy will be

    1. 125 J

    2. 250 J

    3. 500 J

    4. 625 J

  8. An object m0ves along a straight line path from P to Q under the action of a force (4i − 3i + 3k), N. If the coordinates of P and Q, in metres, are (3, 3, 1) and (2, 1; 4) respectively, then the work done by the force, is

    1. + 15J

    2. -15J

    3. 1015 J

    4. V35 (4i − 3j + 2k) J

  9. Which of the following are correct with reference to energy?

    1. It has dimensions of ML2T2

    2. It 1s a scalar.

    3. Its S. 1. Unit is watt.

    4. It can neither be created nor destroyed.

    Select the correct answer using the codes given below:

    1. 1, 2, 3 and 4

    2. 1, 2 and 3

    3. 1, 2 and 4

    4. 1, 3 and 4

  10. Work done in carrying a particle from A to B is independent of the path chosen implies that

    1. the linear momentum is conserved

    2. the angular momentum is conserved

    3. the component 9f angular momentum along the line joining A and B is conserved

    4. the potential function can be defined

  11. If the earth is a point mass of 6 × 1024 kg revolving around the sun at a distance of 1.5 × 108 km and in time r = 3.14 × 107 s, them the angular momentum of the earth around the sun is

    1. 1.2 × 1018 kg m2/s

    2. 1.8 × 1029 kg m2/s

    3. 1.5 × 1037 kg m2/s

    4. 2.7 × 1040 kg m2/s

  12. A particle is moving i0n a circular orbit of radius r1 with an angular velocity w1. It jumps to another circular orbit of radius R2 and attains an angular velocity w2. If r2 = 0.5 r1 and assuming that no external torque is applied to the system, them, the angular velocity, w2 is given by

    1. w2 = 4w1

    2. w2 = 3 w1

    3. w2 = 2 w1

    4. w2 = w1

  13. If a body of mass 45kg resting on a rough horizontal surface can be just moved by a force of 10 kg weight acting horizontally, then the coefficient of sliding friction Is

    1. 4.5

    2. 0.5

    3. 0.45

    4. 0.22

  14. When a satellite moves round the earth, the quantity which remains constant is

    1. angular velocity

    2. kinetic energy

    3. potential energy.

    4. aerial velocity

  15. If a planet revolves round the sun in a circular orbit of radius ‘a’ with a period of revolution T, then (k being a positive constant)

    1. T = k a2/3

    2. T = k a 3/2

    3. T = k a2

    4. T = k a3