JAMB Physics Past Questions & Answers - Page 192

957.

Which of the following statements is correct? The magnetized state of an iron bar can be destroyed completely by

A.

heating the bar to a high temperature

B.

breaking the bar

C.

connecting opposite poles with a small piece of iron

D.

placing the bar inside a strong magnetic field

E.

none of the above

Correct answer is A

No explanation has been provided for this answer.

958.

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

Correct answer is B

No explanation has been provided for this answer.

959.

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

Correct answer is A

No explanation has been provided for this answer.

960.

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

Correct answer is A

Total power = (8 x 40) + (4 x 60) + (2 x 100)

= 760W

Energy(Kwhr) = power x time

= 760 x 10-3 x 150

= 114kwhr.

If, 1kwhr. cost 5k

thus, 114 kwhr. will cost 5 x 114

= N5.70