Physics Past Questions and Answers

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 402:

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 403:

\(500cm^{-3}\) 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 404:

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 \(97.25Nm^{-2}\)

Question 405:

Calculate the time taken to heat 2kg of water from 50°C to 100°C in an electric kettle taking 5A, from a 210V supply. (Specific heat capacity of water = 4200\(kg^{-1}K{-1}\)

A 2.5 minutes
B 5.7 minutes
C 6.7 minutes
D 7.5 minutes
E 9.5 minutes