Physics (AS & A Level) · May / June 2018 · Paper 13 · Question 14

Gas is trapped inside a cylinder by a piston of cross-sectional area A. The piston is not frictionless. The gas is heated and this causes it to expand, pushing back the piston through distance r from position P to position Q. The length of the gas column is then s. Which expression represents the amount of work done by the gas against the atmosphere during this expansion?

1. A(atmospheric pressure) × Ar
2. B(atmospheric pressure) × As
3. C(pressure inside the gas) × Ar
4. D(pressure inside the gas) × As

As printed in the paper