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Physics M.C.Q [1M]

Work and Energy · Bihar Board (BSEB) STD 12 Science (BSEB - English Medium). 20 questions.

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M.C.Q [1M]

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20 questions · timed · auto-graded

Question 11 Mark
The negative of the work done by the conservative internal forces on a system equals the change in:
  1. T​​​​​otal energy.
  2. Kinetic energy.
  3. Potential energy.
  4. None of these.
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Question 21 Mark
A block of mass m slides down a smooth vertical circular track. During the motion, the block is in:
  1. Vertical equilibrium.
  2. Horizontal equilibrium.
  3. Radial equilibrium.
  4. None of these.
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Question 31 Mark
Two springs A and B(kA = 2kB) are stretched by applying forces of equal magnitudes at the four ends. If the energy stored in A is E, that in B is:

  1. $\frac{\text{E}}{2}$

  2. $2\text{E}$

  3. $\text{E}$

  4. $\frac{\text{E}}{4}$

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Question 41 Mark
______ of a two particle system depends only on the separation between the two particles. The most appropriate choice for the blank space in the above sentence is:
  1. Kinetic energy.
  2. Total mechanical energy.
  3. Potential energy.
  4. Total energy.
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Question 51 Mark
A heavy stone is thrown from a cliff of height h with a speed $\nu.$ The stone will hit the ground with maximum speed if it is thrown:
  1. Vertically downward.
  2. Vertically upward.
  3. Horizontally.
  4. The speed does not depend on the initial direction.
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Question 61 Mark
A heavy stone is thrown in from a cliff of height h in a given direction. The speed with which it hits the ground:
  1. Must depend on the speed of projection.
  2. Must be larger than the speed of projectio.
  3. Must be independent of the speed of projection.
  4. May be smaller than the speed of projection.
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Question 71 Mark
The work done by all the forces (external and internal) on a system equals the change in:
  1. Total energy.
  2. Kinetic energy.
  3. Potential energy.
  4. None of these.
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Question 81 Mark
Consider two observers moving with respect to each other at a speed v along a straight line. They observe a bock of mass m moving a distancel on a rough surface. The following quantities will be same as observed by the two observers.
  1. Kinetic energy of the block at time t.
  2. Work done by friction.
  3. Total work done on the block.
  4. Acceleration of the block.
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Question 91 Mark
The kinetic energy force on the particle continuously increases with time.
  1. The resultant force on the particle must be parallel to the velocity at all instants.
  2. The resultant force on the particle must be at an angle less than 90° all the time.
  3. Its height above the ground level must continuously decrease.
  4. The magnitude of its linear momentum is increasing continuously.
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Question 101 Mark
One end of a light spring of spring constant k is fixed to a wall and the other end is tied to a block placed on a smooth horizontal surface. In a displacement, the work done by the spring is $\frac{1}{2}\text{kx}^2.$ The possible cases are:
  1. At spring was initially compressed by a distance x and was finally in its natural length.
  2. It was initially stretched by a distance x and and finally was in its natural length.
  3. It was initially in its natural length and finally in a compressed position.
  4. It was initially in its natural length and finally in a stretched position.
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Question 111 Mark
A particle is acted upon by a force of constant magnitude which is always perpendicular to the velocity of the particle. The motion of the particle takes place in a plane. It follows that:
  1. Its velocity is constant.
  2. Its acceleration is constant.
  3. Its kinetic energy is constant.
  4. It moves in a circular path.
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Question 121 Mark
A block of mass M is hanging over a smooth and light pulley through a light string. T he other end of the string is pulled by a constant force F. The kinetic energy of the block increases by 20J in 1s.
  1. The tension in the string is Mg.
  2. The tension in the string is F.
  3. The work one by the tension on the block is 20J in the above 1s.
  4. The work done by the force of gravity is -20J in the above 1s.
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Question 131 Mark
The work done by the external forces on a system equals the change in:
  1. Total energy.
  2. Kinetic energy.
  3. Potential energy.
  4. None of these.
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Question 141 Mark
The total work done on a particle is equal to the change in its kinetic energy:
  1. Always.
  2. Only if the forces acting on it are conservative.
  3. Only if gravitational force alone acts on it.
  4. Only if elastic force alone acts on it.
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Question 151 Mark
A particle of mass m is attached to a light string of length l, the other end of which is fixed. Initially the string is kept horizontal and the particle is given an upward velocity v. The particle is just able to complete a circle.
  1. The string becomes slack when the particle reaches its highest point.
  2. The velocity of the particle become zero at the highest point.
  3. The kinetic energy of the ball in initial position was $\frac{1}{2}\text{m}\nu^2=\text{mgl}.$
  4. The particle again passes through the initial position.
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Question 161 Mark
No work is done by a force on an object if:
  1. The force is always perpendicular to its velocity.
  2. The force is always perpendicular to its acceleration.
  3. The object is stationary but the point of application of the force moves on the object.
  4. The object moves in such a way that the point of application of the force remains fixed.
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Question 171 Mark
You lift a suitcase from the floor and keep it on a table. The work done by you on the suitcase does not depend on:
  1. The path taken by the suitcase.
  2. The time taken by you in doing so.
  3. The weight of the suitcase.
  4. Your weight.
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Question 181 Mark
A particle is rotated in a vertical circle by connecting it to a string of length l and keeping the other end of the string fixed. The minimum speed of the particle when the string is horizontal for which the particle will complete the circle is:

  1. $\sqrt{\text{gl}}$

  2. $\sqrt{2\text{gl}}$

  3. $\sqrt{3\text{gl}}$

  4. $\sqrt{5\text{gl}}$

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Question 191 Mark
A small block of mass m is kept on a rough inclined surface of inclination $\theta$ fixed in an elevator. The elevator goes up with a uniform velocity v and the block does not slide on the wedge. The work done by the force of friction on the block in time t will be:

  1. zero

  2. $\text{mgvt}\cos^2\theta$

  3. $\text{mgvt}\sin^2\theta$

  4. $\text{mgvt}\sin2\theta$

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Question 201 Mark
Two equal masses are attached to the two ends of a spring of spring constant k. The masses are pulled out symmetrically to stretch the spring by a length x over its natural length. The work done by the spring on each mass is:

  1. $\frac{1}{2}\text{kx}^2$

  2. $-\frac{1}{2}\text{kx}^2$

  3. $\frac{1}{4}\text{kx}^2$

  4. $-\frac{1}{4}\text{kx}^2$

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M.C.Q [1M] - Physics STD 12 Science Questions - Vidyadip