A gas is enclosed in a cylinder fitted with a light frictionless piston and maintained at atmospheric pressure (1.01x105 pa). When 1.06x106J of heat is added to the gas, the volume is observed to increase slowly from 12m to 16.2m (a) Calculate the work done by the gas. (b) The change in internal of the gas O(a) W=0J (b) AU=0 O (a) W=0J (b) AU= 4.2x105J (a) W=4 2x105J (b) AU= 4 2x105J (a) W=4.2x105J (b) AU-6 4x105J