1:22 X 33 7. Tipler PSE An engine using 1 mol of an ideal gas ini- tially at 17.6 L and 360 K performs a cycle consisting of four steps: 1) an isothermal expansion at 360 K from 17.6 L to 39.8 L ; 2) cooling at constant volume to 216 K ; 3) an isothermal compression to its original volume of 17.6 L; and 4) heating at constant volume to its original temperature of 360 K . Find its efficiency. Assume that the heat capacity is 21 J/K and the univer- sal gas constant is 0.08206 L . atm/mol/K = 8.314 J/mol/K. Give your answer in the form of a percentage. AA quest.cns.utexas.edu C