An inventor claims to have developed an engine that during a certain time interval takes in 110 MJ of heat at 415 K, rejects 50 MJ of heat at 212 K while manages to do 16.7 kWh of work. Do you agree with the inventor's claim?

An inventor claims to have developed an engine that during a certain t

1.	An inventor claims to have developed an engine that during a certain time interval takes in 110 MJ of heat at 415 K, rejects 50 MJ of heat at 212 K while manages to do 16.7 kWh of work. Do you agree with the inventor's claim?
Answer» Solution :The claimed EFFICIENCY `eta_(C)=W/Q_(H)=(16.7kWh)/(110MJ)` But as `1 kWh=10^(3)xx(J//s)xx(60xx60s)=3.6MJ` So `eta_(C)=(16.7xx3.6)/110=0.55=55%"………."(1)` while MAXIMUM possible theoretical efficiency, `eta_(MAX)=1-T_(L)/T_(H)=(T_(H)-T_(L))/T_(H)=(415-212)/415=0.49%"……….."(2)` From Eqns. (1) and (2) it is clear that claimed efficiency is greter than maximum possible theoretical efficiency, so inventor.s claim does not APPEAR to be correct.