The three processes in a thermodynamic cycle shown in the figure are: Process $1 \rightarrow 2$ is isothermal; Process $2 \rightarrow 3$ is isochoric (volume remains constant); Process $3 \rightarrow 1$ 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 . Then

• Correct answer
  A

  the net change in the internal energy in the cycle is 0 J .
• Correct answer
  B

  the work done by the gas in the isochoric process is 0 J .
• C

  The change in the internal energy in the adiabatic process is 30 J .
• Correct answer
  D

  the heat added to the system in the isothermal process is 30 J .

Hence, the correct answer is options: 'A', 'B', 'D'.