A certain quantity of an ideal gas initially at temperature T0, pressure P0, and volume V0 is compressed to one-half its initial volume. As shown, the process may be adiabatic (process 1), isothermal (process 2), or isobaric (process 3).
Which of the following is true of the mechanical work done on the gas?
1. It is the same for process 1 and 2 and less for process 3.
2. It is greatest for process 1.
3. It is the same for all three processes.
4. It is the same for process 2 and 3 and less for process 1.
5. It is greatest for process 3.