# Competitive Exams: Physics MCQs (Practice_Test 11 of 35)

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- Assertion (A) : Fission of235 92 U is brought about by a thermal neutron, whereas that of 238 92U is brought about by a fast neutron.
- Reason (R) : 235 92U is an even-odd nucleus, whereas 238 92 U an even-even nucleus

- Assertion (A) : A 14-pin package can accommodate only four two-input gates.
- Reason (R) : A gate requires only three external pins

- Vander Waals equation for real gases is p + (a/v2) (v-b) = RT. The dimensional of ‘a’ will be (symbols have their usual meanings)
- ML5T − 2
- ML3T − 2
- ML3T − 1
- M2LT-2

- A particle is moving in a circular path with a constant speed v. If q is the angular displacement, then starting from q = 0, the maximum and minimum changes in the momentum will occur when value of q is respectively
- 450 and 900
- 900 and 1800
- 1800 and 3600
- 900 and 2700

- The coordinates of a moving particle at time t, are given by x = at2 y = bt2 The speed of the particle is
- 2 (a + b) t
- (a2 + b2) t
- 2 (a2 + b2) t
- (a + b) t

- Body 1 of mass M is dropped from a height of 1 m and 1-body 2 of mass 3 m is dropped from a height of 9m. Ratio of time taken by the bodies 1 and 2 to reach the ground is
- 1: 1
- 1: 3
- 3: 1
- 9: 1

- The resultant of two forces acting at an angle of 1500 is 10 N and is perpendicular to one of the forces. The other force is
- N
- 10 × 3N
- 20N
- 20 × 3 N

- A body of mass m, moving with velocity u collides elastically with another body at rest having mass M. If the body of mass M moves with velocity then the velocity of the body of mass m after the impact is
- m-M/m + M u
- m-M/m + M v
- m + MV/m + M
- m-MV/m + M

- If a body placed at the origin is acted upon by a force F = (i + j + 12 k) , then which of the following statements are correct?
- Magnitude of F is 2 ± 2
- Magnitude of F is 2
- F makes an angle of 450 with the Z axis
- F makes an angle of 30 degree with the Z axis

Select the correct answer using the codes given below:

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

- Which one of the following gives the angle made by the resultant velocity after t seconds for a projectile of initial velocity u, projected at an angle q with the horizontal?
- N/A
- N/A
- N/A
- N/A

- If the horizontal range of a projectile is equal to the maxi-mum height reached, then the corresponding angle of projection is
- tan-1 (1)
- tan-1 (3)
- tan-1 (4)
- tan-1 (12)

- If a person sitting on a rotating stool with his hands out stretched, suddenly lowers his hands, then his
- kinetic energy win decrease
- moment of inertia win decrease
- angular momentum win increase
- angular velocity will remain constant

- Match List I with List II and select the correct answer:
List-I (System) List-II (Expression for moment of inertia) - A ring about its axis
- A uniform circular disc about its axis
- A solid sphere about any diameter
- A solid sphere about any tangent

- MR
- MR2
- MR2
- MR2
- MR2

- A
- B
- C
- D

- 2
- 1
- 3
- 4

- 4
- 3
- 2
- 5

- 1
- 5
- 4
- 3

- 4
- 1
- 2
- 3

- A cylinder of mass 5 kg and radius 0.1 m is resting on a horizontal platform (parallel to the x-y plane) and is free to rotate about its axis fixed along the y-axis. The platform is given a motion, v in the x direction given by x == 0.2 cos (10t) m. If there is no slipping, then the maximum torque acting on the cylinder during its motion is
- 0.2 N-m
- 2.0 N-m
- 5.0 N-m
- 10.0 N-m

- A stone of mass M tied at the end of a string, is moving in a circle of radius R, with a constant angular velocity w. The work done on the stone, in any half circle, is
- p MR2 w2
- 2 MR2 w2
- MR 2 w2
- zero