An alpha nucleus of energy 12 mv2 bombards a heavy

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 Multiple Choice QuestionsMultiple Choice Questions

111.

Which of the following is not an inelastic collision ?

  • A man jump on a cart

  • A bullet embedded in a block

  • Collision of two glass ball

  • none of the above


112.

A force F acting on an object varies with distance x as shown here. The force is in newton and distance is in metre. The work done by the force in moving the object from x = 0 to x = 6 m is

  • 4.5 J

  • 13.5 J

  • 9.0

  • 18.0 J


113.

A 5 A fuse wire can withstand a maximum power of 1 W in circuit. The resistance of the fuse wire is

  • 0.2 Ω

  • 5 Ω

  • 0.4 Ω

  • 0.04 Ω


114.

A particle of mass 100 g is thrown vertically upwards with a speed of 5 m/s. The work done by the force of gravity during the time the particle goes up is

  • -0.5 J

  • -1.25 J

  • 1.25 J

  • 0.5 J


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115.

A mass of M kg is suspended by a weightless string. The horizontal force that is required to displace it until the string makes an angle of 45° with the initial vertical direction is

  • Mg 2 + 1

  • Mg 2

  • Mg2

  • Mg 2 -1


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116.

An alpha nucleus of energy 12 mv2 bombards a heavy nuclear target of charge Ze. Then the distance of closest approach for the alpha nucleus will be proportional to

  • v2

  • 1/ m

  • 1/ν4

  • 1/ Ze


B.

1/ m

Since, here nuclear target is heavy it can be assumed safely that it will remain stationary and will not move due to the Coulombic interaction force.

At distance of closest approach relative velocity of two particles is v. Here target is considered as stationary, so a-particle comes to rest instantaneously at distance of closest approach. Let the required distance is 'r'  then from work energy-theorem.

The change in kinetic energy of a particle is equal to the work done on it by the net force.

0 - mv22 = -14πεo Ze × 2e r       r     1m       r    1ν2       r    Ze2


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117.

For inelastic collision between two spherical rigid bodies

  • the total kinetic energy is conserved

  • the total mechanical energy is not conserved

  • the linear momentum is not conserved

  • the linear momentum is conserved


118.

300 J of work is done in sliding a 2 kg block up an inclined plane of height 10 m. Taking g =10 m/s2, work done against friction is

  • 200J

  • 100 J

  • zero

  • 1000 J


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119.

A motor cycle is going on an overbridge of radius R. The driver maintains a constant speed. As the motor cycle is ascending on the overbridge, the normal force on it

  • increases

  • decreases

  • remains the same

  • fluctuates erratically


120.

If we throw a body upwards with velocity of 4 m/s, at what height does its kinetic energy reduce to half of the initial value? ( Take g = 10 ms-1 )

  • 4 m

  • 2 m

  • 1m

  • 0.4 m


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