JAMB Physics Past Questions & Answers - Page 54

266.

In the molecular explanation of conduction, heat is transferred by the

A.

In the molecular explanation of conduction, heat is transferred by the

B.

Free atoms

C.

Free molecules

D.

Free solids

Correct answer is A

- Conduction is explained in terms of the free electrons.
- Convention is explained in terms of the movement of the fluid involved.
- Radiation is explained in terms of invisible electromagnetic wave

268.

During the transformation of matter from the solid to the liquid state, the heat supplied does not produce a temperature increase because

A.

the heat energy is quickly conducted away

B.

the heat capacity has become very large as the substance melts

C.

the heat gained is equal to the heat lost by the substance

D.

all the heat is used to break the bonds holding the molecules of the solid together

Correct answer is D

During the transformation of matter from the solid to the liquid state, the heat supplied does not produce a temperature increase because all the heat is used to break the bonds holding the molecules of the solid together

270.

An alternating current can induce voltage because it has

A.

ripple value

B.

varying magnetic field

C.

weaker magnetic field than direct current

D.

high peak value

Correct answer is B

As induced voltage is produced by varying magnetic field. The induced voltage is proportional to the rate of change of magnetic flux linking the coil.