Waec Physics 1994 Past Questions and Answers

Question 36:

• WAEC 1994

A metal rod of length 40cm at 20°C is heated to a temperature of 45°C. If the new length of the rod is 40.05cm. Calculate its linear expansitivity

A. 1.2 x \(10^{-5}K{-1}\)
B. 2.5x \(10^{-5}K{-1}\)
C. 3.5x \(10^{-5}K{-1}\)
D. 4.5x \(10^{-5}K{-1}\)
E. 5x \(10^{-5}K{-1}\)

Question 37:

• WAEC 1994

500g of water is heated so that its temperature rises from 30°C to 72°C in 7 minutes. calculate the supplied per minute. (Specific heat capacity of water is 4200J\(kg^{-1}K^{-1}\)

A. 9000J
B. 12600J
C. 21000J
D. 25200J
E. 88200J

Question 38:

• WAEC 1994

An electric kettle rated 1500W boils away 0.3kg of a liquid at its boiling point every 300s. Calculate the specific latent heat of the vaporisation of the liquid

A. 1.5 x \(10^6Jkg^-1\)
B. 1.35 x \(10^6Jkg^-1\)
C. 1.5 x \(10^5Jkg^-1\)
D. 4.5 x \(10^2Jkg^-1\)
E. 3 x \(10^2Jkg^-1\)

Question 39:

• WAEC 1994

\(500cm^{-3}\) of a gas is collected at 0°C and at a pressure of 72cm of mercury. What is the volume of the the gas at the same temperature and at a pressure of 76cm of the same mercury?

A. \(\frac{76\times500}{72}cm^3\)
B. \(\frac{72\times500}{76}cm^3\)
C. \(\frac{72\times76}{500}cm^3\)
D. \(\frac{76}{72\times500}cm^3\)
E. \(\frac{72}{76\times500}cm^3\)

Question 40:

• WAEC 1994

The pressure of air in a tire is \(22.5Nm^{-2}\) at 27°C. If the air in the tyre heats up to 47°C, calculate the new pressure of the air, assuming that no air leaks out and that the change in volume of the air can be neglected.

A. \(21.10Nm^{-2}\)
B. \(24Nm^{-2}\)
C. \(39.07Nm^{-2}\)
D. \(45Nm^{-2}\)
E. \(97.25Nm^{-2}\)