Two Carnot engines A and B are operated in succession. The first one, A receives heat from a source at T1 = 800 K and rejects to sink at T2 K. The second engine B receives heat rejected by the first engine and rejects to another sink at T3 = 300 K. If the work outputs of two engines are equal, then the value of T2 is
The correct option is C. 550 K.
The efficiency of a Carnot engine is given by,
η=TSource−TSinkTSource
⇒ηA=T1−T2T1=WAQ1 and
ηB=T2−T3T2=WBQ2
∴Q1Q2=T1T2×T2−T3T1−T2
∵ WA=WB and Q1Q2=T1T2
T1T2=T1T2×T2−T3T1−T2
∴T2=T1+T32=800+3002=550 K.