20.43 . CALC A heat engine operates using the cycle shown P in Fig. P20.43. The working substance is 2.00 mol of helium gas, which reaches a maximum temperature of 327°C. Assume the helium can be treated as an ideal gas. Process bc is isother- mal. The pressure in states a and c is 1.00 * 105 Pa, and the pressure in state b is 3.00 * 105 Pa. (a) How much heat O enters the gas and how much

 20.43  . CALC  A  heat   engine operates using the cycle shown P in  Fig.  P20.43.  The  working         substance is 2.00 mol of helium gas, which reaches a maximum temperature of 327°C. Assume the helium can be treated as an ideal gas. Process bc is isother- mal. The  pressure  in  states  a and c is 1.00 *  105  Pa, and the   pressure in state b is 3.00 * 105  Pa. (a)  How  much  heat      O enters the gas and how much 

leaves the gas each cycle? (b) How much work does the engine do each cycle, and what is its efficiency? (c) Compare this engine’s efficiency with the maximum possible efficiency attainable with the hot and cold reservoirs used by this cycle.