1.

A Carnot engine, whose efficiency is 40%, takes in heat from a source maintained at a temperature of 500 K. It is desired to have an engine of efficiency 60%. Then, the intake temperature for the same exhaust (sink) temperature must be :

Answer»

600 K
efficiency of Carnot engine cannot be made larger than 50%
1200 K
750 K.

Solution :CASE I: `eta =1-(T_(2))/(T_(1))`
`(400)/(100) =1-(T_(2))/(T_(1))=1-(T_(2))/(500)`
`rArr (T_(2))/(500) =1-(40)/(100)=(60)/(100)`
`rArr T_(2) =(60)/(100xx500=300 K`
Case II: `eta =(1-(T_(2))/(T_(1))) rArr (60)/(100)=1-(300)/(T_(1))`
`rArr (300)/(T_(1)) =1-(60)/(100)=(40)/(100)`
`rArr T_(1)=(300xx100)/(40)=(3000)/(4)=750 K`
Correct CHOICE : (d).


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