Jamb Physics 1991 Past Questions and Answers

Question 21:

• JAMB 1991

A boy timed 30 oscillations of a certain pendulum thrice and obtained 1min. 10s, 1min. 12s and 1min. 7s respectively.The mean period of oscillation of the pendulum is

A. 0.14s
B. 0.43s
C. 2.32s
D. 6.97s

Question 22:

• JAMB 1991

Which of the following is TRUE of light and sound waves?

A. They both transmit energy
B. They both need a mediumfor propagation
C. They are both transverse waves
D. Their velocities in air are equal

Question 23:

• JAMB 1991

The image in a pin-hole camera is

A. Errect and formed by refraction through a lens
B. Virtual and formed by dispersion
C. Erect and gets sharper as the hole becomes larger
D. Inverted and formed by the light from each point travelling in a straight line

Question 24:

• JAMB 1991

When a plane mirror at which a ray is incident is rotated through an angle \( \theta \), the reflected ray will be rotated through

A. \(\frac{1}{2}\)\(\theta\)
B. \(\theta\)
C. 2\(\theta\)
D. 3\(\theta\)

Question 25:

• JAMB 1991

A trough 12.0cm deep is filled with water of refractive index \(\frac{4}{3}\). By how much would a coin at the bottom of the trough appear to be displaced when viewed vertically from above the water surface?

A. 3.0cm
B. 6.0cm
C. 9.0cm
D. 16.0cm