JAMB Physics Past Questions & Answers - Page 213

1,061.

A hot metal ball is suspended in the open air. As it cools it loses heat by?

A.

conduction only

B.

convection only

C.

radiation only

D.

conduction and convection

E.

convection and evaporation

Correct answer is B

Convection occurs when heat is carried away from your body via moving air. If the surrounding air is cooler, the air will absorb heat and rise.

As the warmed air rises, cooler air moves in to take its place and absorb more warmth. 

1,062.

The area under a force-distance graph represents

A.

acceleration

B.

velocity

C.

power

D.

work

E.

momentum

Correct answer is D

No explanation has been provided for this answer.

1,063.

The equation PxVyTz = constant

A.

x = 0, y = 0, z = 1

B.

x = 1, y = 0, z = 0

C.

x = 1, y = 1, z = 0

D.

x = 1, y = 1, z = 1

E.

x = 1, y = 1, z = -1

Correct answer is E

No explanation has been provided for this answer.

1,064.

A magnetic needle is suspended first at the earth's north magnetic pole and then at a point on the magnetic equator. The respective angles between the needle and the horizontal are

A.

0o and 0o

B.

60o and 60o

C.

90o and 90o

D.

90o and 0o

E.

0o and 90o

Correct answer is D

No explanation has been provided for this answer.

1,065.

A high-resistance voltmeter reads 3.0V when connected across the terminals of a battery on open circuit and 2.6V when the battery supplies a current of 0.2A through a lamp. The resistance of lamp is

A.

2.00\(\Omega\)

B.

13.00\(\Omega\)

C.

0.52\(\Omega\)

D.

0.13\(\Omega\)

E.

1.50\(\Omega\)

Correct answer is B

IR = 2.6 and Ir = 0.4

0.2 x R = 2.6

R = 13.00\(\Omega\)