Question 71:

• JAMB 1979

A man standing between two parallel mirrors in a barber's shop will see the following number of his own image

A. Eight
B. Two
C. Four
D. One
E. Infinite

Question 72:

• JAMB 1979

Which of the following statements is incorrect? The sensitivity of a galvanometer which incorporates an optical lever arrangement may be increased by providing

A. A larger number of turns in the coil
B. A thinner suspension with a small torsional control
C. A special alloy permanent magnet which gives a high magnetic flux
D. All of the above
E. A light source with a greater intensity

Question 73:

• JAMB 1979

A landlord has eight 40W electric light bulbs, four 60W bulbs and two 100W bulb in his house. If he has all the points on for five hours daily and if N.E.P.A. charges 5k per unit, his bill for 30 days is

A. N5.70
B. N7.23
C. N3.65
D. N8.05
E. N4.50

Question 74:

• JAMB 1979

Which of the following statements is correct? The reading of pressure on a mercury barometer is independent of

A. The cross-sectional area of the tube
B. The atmospheric pressure
C. The density of mercury
D. The temperature of mercury
E. The acceleration due to gravity

Question 75:

• JAMB 1979

What are the units of thermal conductivity?

A. Kg.m.sec²
B. Joule sec^-1m^-1k^-1
C. Kg.m
D. Newton sec^-1m²
E. M³