KVPY SX SB Exam 2013 Question Paper

The three processes in a thermodynamic cycle shown in the figure are : Process 1 → 2 is isothermal; Process 2 → 3 is isochoric (volume remains constant); Process 3 → 1 is adiabatic. The total work done by the ideal gas in this cycle is 10 J. The internal energy decreases by 20 J in the isochoric process. The work done by the gas in the adiabatic process is -20 J. The heat added to the system in the isothermal process is