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 kW hours of work. Do you agree with the inventors's claim?

Explanation

The claimed efficiency
`eta=W/Q_(H)=(16.7kWh)/(10MJ)`
But as `1kWh=10^(3)xx(J//s)xx(60xx60s)=3.6MJ`
So `eta=(16.7xx3.6)/110=0.55=55%` .......(i)
While maximum possible theoretical efficiency,
`eta_(max)=-T_(L)/T_(H)=(T_(H)-T_(L))/T_(H)=(415-212)/415`
`=.49= 49%`
From eqns.(i) and (ii) it is clear that claimed efficiency is greater than maximum possible theoretical efficiency, so inventor's c claim does not appear to be correct.