A Carnot engine takes in heat from a reservoir of heat at `427^(@)C`. How many calories of heat must it take from the reservoir in order to procuce useful mechanical work at the rate of `357 watt`?

Explanation

Here, `T_(1)= 427^(@)C = 427+273`
`=700K`
`T_(2)= 77^(@)C= (77+273)K= 350K`,
`Q_(1)=?, W=357 "watt"`,
As `(Q_(2))/(Q_(1))= (T_(2))/(T_(1))`
`:. (Q_(1)-W)/(Q_(1))= (350)/(700)= 1/2`
`Q_(1)-W= (Q_(1))/2 or (Q_(1))/2=W`,
`Q_(1)= 2W=2xx357= 714 "watt"`
`=(714)/(4.2)cal//s= 170 cal//s`