A train, when passing a station with a speed of 108 km/h, beeps with a 740 Hz frequency sound. What is the sound frequency of the whistle heard by a person at the station, when the train moves away? Consider the speed of sound in the air equal to 340 m/s

If the heat engine is a perfect carnot cycle engine, thenefficiency = (t2-t1)/t2   where t1=temperature of cold reservoir ( ° k) = 135            t2=temperature of hot reservoir ( ° k)   = 325thereforeefficiency = (t2-t1)/t2 = (325-135)/325 = 0.5846 = 58%  note: this is the theoretical maximum efficiency of a perfect heat engine.   real-life engines do not achieve this value.