Q.
The efficiency of Car not engine is 50% and temperature of sink is 500K. If the temperature of source is kept constant and its efficiency is to be raised to 60%, then the required temperature of the sink will be:
Efficiency of the Carnot engine is given by η=1−T1T2..(i)
where T1= temperature of source T2= temperature of sink
Given, η=50
Substituting in relation (i), we have or 0.5=1−T1500 or T1500=0.5 ∴T1=0.5500=1000K
Now, the temperature of sink is changed to T2 and the efficiency becomes 60%
i.e, 0.6. Using relation (i), we get 0.6=1−1000T2
or 1000T2=1−0.6=0.4
or T2=0.4×100=400K
Carnot engine is not a practical engine because many ideal situations have been assumed while designing this engine which can practically not be obtained.