Hi, I would appreciate any help with this: A monatomic ideal gas is used as the working substance for the Carnot cycle. Processes A => B and C => D are isothermal, while processes B => C and D => A are adiabatic. During process A => B, there are 400 J of work done by the gas on the surroundings. How much heat is expelled by the gas during process C => D? So I'm completely stuck, all I know is that it's less than 400 J, obviously. There's a picture of the corresponding PV graph actually at http://www.compadre.org/psrc/evals/Physics_Bowl_2003.pdf (page 12). Thanks for any help!!