JAMB Physics Past Questions & Answers - Page 307

1,531.

If a room is saturated with water vapour, the temperature of the room must be

A.

at 0oC

B.

above the dew point

C.

at 100oC

D.

below or at the dew point

Correct answer is D

No explanation has been provided for this answer.

1,533.

When 100g of liquids L1 at 78°C was mixed with Xg of liquid L2 at 50°C, the final temperature was 66°C. Given that the specific heat capacity of L2is half that of L1, find x

A.

50g

B.

100g

C.

150g

D.

200g

Correct answer is C

Heat lost by L1 = heat gained by L2

cL1 = 2cL2

100 x 2cL2 x (78 - 66)

= xg x cL2 x (66 - 50)

xg = 150g

1,534.

A Motor Tyre is inflated to pressure of 2.0 x 105Nm-2 when the temperature of air is 27oC. What will be the pressure in it at 87oC assuming that the volume of the Tyre does not change?

A.

2.6 x 105Nm-2

B.

2.4 x 105Nm-2

C.

2.2 x 105Nm-2

D.

1.3 x 105Nm-2

Correct answer is B

\(\frac{p_1}{T_1}\) = \(\frac{p_2}{T_2}\)

\(\frac{2 \times 10^5}{27 + 273}\) = \(\frac{p_2}{87 + 273}\)

P2 = 2.4 x 105Nm-2

1,535.

The melting point of naphthalene is 78oC. What is this temperature in kelvin

A.

100k

B.

351k

C.

378k

D.

444k

Correct answer is B

T = 78 + 273

= 351k