A litre of dry air at STP expands adiabatically to a volume of 3 litres. If  γ=1.40, the work done by air is: (31.4=4.6555) [ Take air to be an ideal gas)

Given  : P1=1atm,  T1=273K, V1V2 =13            Adiabatic Process, P1V1γ=P2V2γ               Final Pressure, P2=P1V1V2γ =1atm131.4 = 14.6555=0.215 atmNow , work done in adiabatic process  =P1V1−P2V2γ−1=(1)(1)−(0.215)(3)1.4−1=0.8875 atm−lt  =0.8875×1.01325×105 Pa ×10−3 m3 = 89.9J ≃90.5 J (closest)