WAEC Physics Past Questions & Answers - Page 198

986.

Humidity is used to describe the amount of

A.

air in water vapour

B.

cloud available in the atmosphere

C.

air in equal volume of cloud

D.

water vapour in the amosphere

Correct answer is D

No explanation has been provided for this answer.

987.

Which of the following physical qualities affects the saturated vapour pressure of a liquid?

A.

temperature

B.

volume

C.

mass

D.

density

Correct answer is A

No explanation has been provided for this answer.

988.

The amount of heat given out or absorbed when a substance changes its state at a constant temperature is known as

A.

latent heat

B.

heat capacity

C.

specific latent heat

D.

specific heat capacity

Correct answer is A

No explanation has been provided for this answer.

989.

The volume of an ideal gas at a pressure of 77cmHg and temperature 60oC is 24cm3. If the temperature and pressure are increased to 98oC
and 81cmhg respectively, calculate the new volume of the gas

A.

411.5cm3

B.

267.1cm3

C.

254.2cm3

D.

112.7cm3

Correct answer is C

V2 = \(\frac{P_1V_1T_2}{P_2T_1} = \frac{77 \times 240 \times 371}{81 \times 333}\)

= 254.2cm3

990.

A given mass of an ideal gas has a pressure of 500Nm-2 at -13oC. If its volume remains constant. Calculate its pressure at 247oC.

A.

25Nm-2

B.

50Nm-2

C.

500Nm-2

D.

1000Nm-2

Correct answer is D

\(P_2 = \frac{p_1 \times T_2}{T_1} = \frac{500 - 520}{65}\)

= 1000Nm-2