WAEC Physics Past Questions & Answers - Page 140

696.

Which of the following wave is electromagnetic?

A.

x-rays

B.

sound waves

C.

water waves

D.

tidal waves

Correct answer is A

No explanation has been provided for this answer.

697.

The pressure of a fixed mass of an ideal gas at 27°C is 3 pa. The gas is heated at a constant volume until its pressure is 5 pa. Determine the new temperature of the gas.

A.

100oC

B.

227oC

C.

273oC

D.

500oC

Correct answer is B

\(\frac{P_1}{T_1} = \frac{P_2}{T_2} = \frac{3}{300} = \frac{5}{T_2}\)

T\(_2\) = 500°C

°C = 500 - 273 = 227°

700.

A relative density bottle of volume 50cm3 is completely filled with a liquid at 30oC. It is then heated to 80oC such that 0.75cm3 of the liquid is expelled. Calculate the apparent cubic expansivity of the liquid.

A.

0.00030k-1

B.

0.00032k-1

C.

0.01970k-1

D.

0.02030k-1

Correct answer is A

Ya = \(\frac{\text{Vol. expelled}}{\text{Vol. left x temp. change}} = \frac{0.75}{49.25 \times 50}\)

= 0.00030k-1