VA = VD, VB = VC. Curves AB and CD are isotherms; AD and BC are isochores. An ideal heat engine uses 0.03 mole of an ideal gas and operates between a hot reservoir at TH = 500 K and cold reservoir at

 VA = VD, VB = VC. Curves AB and CD are isotherms; AD and BC are isochores.

 An ideal heat engine uses 0.03 mole of an ideal gas and operates between a hot reservoir at TH = 500 K and cold reservoir at TL = 320 K, in a cycle from A → B → C → D → A. From A → B the gas undergoes an isothermal expansion, changing its volume from VA to 5.5VA . From B → C, the pressure is reduced at a constant volume. From C → D, the gas undergoes an isothermal compression, and from D → A, the pressure is increased at a constant volume until the gas is back at the original state A. If the engine operates at 55 cycles per second, the power output is

A) 7.37 kW B) 6.31 kW C) 4.21 kW D) 2.10 kW E) 3.16 k