Whenever a stream of electrons collides with a stream of photons, in this collision, which of the following is not conserved?

• Linear momentum

• Total energy

• No. of photons

• No. of electrons

Two projectiles of same mass have their maximum kinetic energies in ratio 4:1 and ratio of their maximum height is also 4:1 then what is the ratio of their ranges?

• 2 : 1

• 4 : 1

• 8 : 1

• 16 : 1

What is moment of inertia of a cylinder of radius r, along its height?

• mr²

• mr²/2

• 2 mr²/5

• mr²/5

The position of a particle moving in the x-y plane at any time t is given by; x = ( 3t³ $-$ 6t ) meters;  y = ( t² - 2t) meters. Select the correct statement.

• acceleration  is  zero  at  t = 0

• velocity  is  zero  at  t = 0

• velocity  is  zero  at  t = 1s

• velocity  and  acceleration of the particle are never zero

A block of mass  m  is pulled along a horizontal surface by applying a force at an angle θ with the horizontal. If the block travels with a uniform velocity and has a displacement  d  and the coefficient of friction is  μ  then the work done by the applied force is

• $\frac{\mathrm{\mu } \mathrm{mg} \mathrm{d}}{\mathrm{cos\theta } + \mathrm{\mu } \mathrm{sin\theta }}$

• $\frac{\mathrm{\mu } \mathrm{mg} \mathrm{d} \mathrm{cos\theta }}{\mathrm{cos\theta } + \mathrm{\mu } \mathrm{sin\theta }}$

• $\frac{\mathrm{\mu } \mathrm{mg} \mathrm{d} \mathrm{sin\theta }}{\mathrm{cos\theta } + \mathrm{\mu } \mathrm{sin\theta }}$

• $\frac{\mathrm{\mu } \mathrm{mg} \mathrm{d} \mathrm{cos\theta }}{\mathrm{cos\theta } - \mathrm{\mu } \mathrm{sin\theta }}$

In figure, a particle having mass m = 5 g and large  q'= 2 x 10^-9  starts from rest at point  $𝑎$ and moves in a straight line to point b. What is its speed  v at point  b?

• 2.65 cms^-1

• 3.65 cms^-1

• 4.65 cms^-1

• 5.65 cms^-1

Four holes of radius Rare cut from a thin square plate of side 4R and mass M. The moment of inertia of the remaining portion about z-axis is

• $\frac{\mathrm{\pi }}{12} {\mathrm{MR}}^2$

• $\left(\frac{4}{3} - \frac{\mathrm{\pi }}{4}\right) {\mathrm{MR}}^2$

• $\left(\frac{4}{3} - \frac{\mathrm{\pi }}{6}\right) {\mathrm{MR}}^2$

• $\left(\frac{8}{3} - \frac{10\mathrm{\pi }}{16}\right) {\mathrm{MR}}^2$

A block of mass  10 kg  is moving in x-direction with a constant speed of 10 m/s. It is subjected to a retarding force F = 0·1 x joule /metre during its travel from  x= 20 m  to  x = 30 m. Its final KE will be

• 475 J

• 450 J

• 275 J

• 250 J

Which of the following pairs does not have same dimensions ?

• impulse and momentum

• moment of inertia and moment of force

• angular momentum and Planck's constant

• work and torque

Assertion: Two balls of different masses are thrown vertically upward with same speed. They will pass through their point of projection in the downward direction with the same speed. 

Reason: The maximum height and downward velocity attained at the point of projection are independent of the mass of the ball.

• If both assertion and reason are true and reason is the correct explanation of assertion.

• If both assertion and reason are true but reason is not the correct explanation of assertion.

• If assertion is true but reason is false.

• If both assertion is true but reason is false.