Waec Physics 2000 Past Questions and Answers

Question 21:

• WAEC 2000

A piece of metal of mass 50g is cooled from 80^oC to 20^oC. Calculate the amount of heat lost. (specific heat capacity of the material of metal = 450Jkg^-1K^-1)

A. 4.50 x 10³J
B. 2.25 x 10³J
C. 1.80 x 10³J
D. 1.35 x 10³J

Question 22:

• WAEC 2000

The mass of water vapour in a given volume of air is 0.05g at 20^oC, while the mass of water vapour required to saturate it at the same temperature is 0.15g. Calculate the relative humidity of the air

A. 3.33%
B. 5.55%
C. 33.33%
D. 55.55%

Question 23:

• WAEC 2000

The temperature at which the saturated vapour pressure of a liquid is equal to the external atmospheric pressure is known as its

A. Dew point
B. Boiling point
C. Lower fixed point
D. Tripple point

Question 24:

• WAEC 2000

A periodic pulse travels a distance of 20.0m in 1.00s. If its frequency is 2.0 x 10³Hz. Calculate the wavelength.

A. 1.0 x 10^-3m
B. 1.0 x 10^-2m
C. 2.0 x 10^-2m
D. 1.0 x 10²m

Question 25:

• WAEC 2000

A wave has an amplitude equal to 4.0m, angular speed \(\frac{1}{3} \pi\) rads^-1 and phase angle \(\frac{2}{3} \pi\) rad. The displacement y of the wave particle is given as

A. Y = 4 sin \(\frac{\pi}{3}\)(t + 2)
B. Y = 4 sin \(\frac{\pi}{3}\)(t + \(\frac{2}{\pi}\)
C. Y = 4 sin \(\frac{\pi}{3} (2t + 1)\)
D. Y = 4 sin \(\frac{\pi}{3} (t + 2)