Answer (C)
Process – I is an adiabatic process
It is a type of process which occurs without transferring of heat or mass between the system and its surrounding. It transfers energy to the surroundings only as work.
Therefore, ΔQ=ΔU+ΔW
Now, ΔQ=0
Therefore, W=−ΔU
Now, the volume of gas is decreasing, then W<0 and ΔU>0
=> Temperature of gas increases.
=> No heat is exchanged between the gas and surrounding.
Process – II is an isobaric process
In this process Pressure remain constant.
W = P ΔV = 3P0[3V0 – V0] = 6P0V0
Process - III is an isochoric process
It is a type of process where volume remains constant, so
ΔQ = ΔU + W
W = 0
Therefore, ΔQ=ΔU
Process – IV is an isothermal process
In this process Temperature remains constant.
ΔQ = ΔU + W
ΔU = 0