# Punjab PSC Exam: Physics MCQs (Practice_Test 17 of 35)

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- 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) - Angular momentum
- Torque
- Surface tension
- Coefficient of viscosity

- ML-1 T − 1
- MT-2
- ML2 T − 1
- ML1 T − 2

- A
- B
- C
- D

- 4
- 3
- 2
- 1

- 3
- 4
- 2
- 1

- 1
- 4
- 2
- 3

- 3
- 1
- 4
- 2

- The dimension of centripetal force is
- L2/T2
- L2/T
- L/T2
- 1/T2

- 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
- 2 p
- V2p
- pV2 + 4
- p

- Two forces each of magnitude 2N, act at an angle of 600. The magnitude of the resultant force is
- V1.1 Newton
- V4 Newton
- V12 Newton
- V14.9 Newton

- 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 m/s
- 5 m/s
- 7 m/s
- 10 m/s

- 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
- is zero at all times
- is constant but not zero
- varies with position
- cannot be defined

- 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
- 125 J
- 250 J
- 500 J
- 625 J

- 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
- + 15J
- -15J
- 1015 J
- V35 (4i − 3j + 2k) J

- Which of the following are correct with reference to energy?
- It has dimensions of ML2T2
- It 1s a scalar.
- Its S. 1. Unit is watt.
- It can neither be created nor destroyed.

Select the correct answer using the codes given below:

- 1,2, 3 and 4
- 1,2 and 3
- 1,2 and 4
- 1,3 and 4

- Work done in carrying a particle from A to B is independent of the path chosen implies that
- the linear momentum is conserved
- the angular momentum is conserved
- the component 9f angular momentum along the line joining A and B is conserved
- the potential function can be defined

- 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
- 1.2 × 1018 kg m2/s
- 1.8 × 1029 kg m2/s
- 1.5 × 1037 kg m2/s
- 2.7 × 1040 kg m2/s

- 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
- w2 = 4w1
- w2 = 3 w1
- w2 = 2 w1
- w2 = w1

- 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
- 4.5
- 0.5
- 0.45
- 0.22

- When a satellite moves round the earth, the quantity which remains constant is
- angular velocity
- kinetic energy
- potential energy.
- aerial velocity

- 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)
- T = k a
- T = k a
- T = k a2
- T = k a3