JAMB Physics Past Questions & Answers - Page 185

921.

A gas at pressure PNm\(^{-2}\) and temperature 27°C is heated to 77°C at constant volume. The new pressure is

A.

0.85 PN-m-2

B.

0.86 PN-m-2

C.

1.16 PN-m-2

D.

1.18 PN-m-2

E.

2.85 PN-m-2

Correct answer is C

At constant volume,

\(\frac{P_1}{T_1}\) = \(\frac{P_2}{T_2}\)

\(\frac{P}{27 +273}\) = \(\frac{P_2}{77 + 273}\)

\(300P_2 = 350P\)

P2 = 1.16 PNm\(^{-2}\)

922.

The latent heat of fusion of ice is 80cal g-1. How much heat is required to change 10g of ice at QoC into water at the same temperature?

A.

80 cal

B.

10 cal

C.

8 cal

D.

800 cal

E.

400 cal

Correct answer is D

Quantity of heat = ml

= 10 x 80

= 800 cal

923.

A temperature 20°C is the same as

A.

36oF

B.

68oF

C.

11.1oF

D.

43.1oF

E.

25oF

Correct answer is B

212°F ... 100°C

\(\theta\)°F ... 20°C

32°F ... 0°C

\(\frac{\theta - 32}{212 - 32}\) = \(\frac{20 - 0}{100 - 0}\)

180 = 5(\(\theta\) - 32)

5\(\theta\) = 180 + 160 = 340

\(\theta\) = 68°F

924.

A few grains of table salt were put in a cup of water, kept at constant temperature and left undisturbed. Eventually all the water tasted salty. The action is due to

A.

convection

B.

osmosis

C.

capillarity

D.

diffusion

E.

conductivity

Correct answer is D

No explanation has been provided for this answer.