Post Utme Physics Past Questions and Answers

Question 121:

A body of mass \(100 \mathrm{~g}\) moves with a velocity of \(10.0 \mathrm{~ms}^{-1}\) and collides with a wall.
After the collision, the body moves with a velocity of \(2.0 \mathrm{~ms}^{-1}\) in the opposite direction. The change in momentum is ____________

A. \(8.0 \mathrm{Ns}\)
B. \(1.2 \mathrm{Ns}\)
C. \(12.0 \mathrm{Ns}\)
D. \(80 \mathrm{Ns}\)

Question 122:

A \(12 \mathrm{~V}\) battery supplying a current of \(20 \mathrm{~A}\) was used to melt \(1.5 \mathrm{~kg}\) of ice at \(0^{\circ} \mathrm{C}\).

Calculate the time required if the lateni: heat of fusion of ice is \(336 \times 10^{3} \mathrm{~J} / \mathrm{Kg}\).

A. \(35.0 \mathrm{~min}\)
B. \(3.5 \mathrm{~min}\)
c. \(76 \mathrm{~min}\)
C. \(21.0 \mathrm{~min}\)

Question 123:

The light from the sun reaches the earth mainly by ____________

A. Convection
B. Conduction
C. Radiation
D. Reflection

Question 124:

One valid assumption of the kinetic theory of gases is that ____________

A. The molecules are in random motion and the number of collisions is constant
B. The number of molecules increases with the pressure
C. The molecules of the gas are all identical and are very small in size
D. The number of molecules increases with temperature

Question 125:

An astronomical telescope is said to be in normal adjustment when the ____________

A. Eye is accommodated
B. Focal length or objective lens is longer than that of the eye piece
C. Final image is at the near point of the eye
D. Final image is at infinity