Air is expanded from 50 liter to 150 liter at 2 atmospheric pressure ( 1 atm = pressure =105Pa). The external work done is:
Given,
Pressure, P=2×105pa
Change in volume, ΔV=150−50=100litre=0.1m3
Work done =PΔV=2×105×0.1=2×104kJ
Hence, work done is 2×104J