60 A three-step cycle is undergone by 3.4mol of an ideal diatomic gas:(1) the temperature of the gas is increased from 200K to 500K at constant volume; (2) the gas is then isothermally expanded to its original pressure;(3) the gas is then contracted at constant pressure back to its original volume.Throughout the cycle,the molecules ro- tate but do not oscillate.What is the efficiency of the cycle?