Jamb Physics 1999 Past Questions and Answers

Question 21:

• JAMB 1999

The inside portion of part of a hollow metal sphere of diameter 20cm is polished. The portion will therefore form a

A. Concave mirror of focal length 5cm
B. Concave mirror of focal length 10cm
C. Convex mirror of focal length 5cm
D. Convex mirror of focal length 20cm

Question 22:

• JAMB 1999

The velocities of light in air and glass are 3.0 x 10⁸ms^-1 and 2.0 x 10⁸ms^-1 respectively. If the angle of refraction is 30°, the sine of the angle of incidence is

A. 0.33
B. 0.50
C. 0.67
D. 0.75

Question 23:

• JAMB 1999

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

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

Question 24:

• JAMB 1999

Which of the following electromagnetic waves is least energetic?

A. Infra-red rays
B. X-rays
C. Ultra-violet rays
D. Gamma rays

Question 25:

• JAMB 1999

Steel is more suitable for permanent magnet than iron because the former

A. Is easily demagnetized by shaing vigorously
B. Is an alloy of many metals
C. Is easily magnetized by alternating current through one cycle
D. Retains magnetism more than iron