InterviewSolution
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InterviewSolution
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Two Carnot engines are operated in succession. The first engine receives heat from a source at `T=800K` and rejects to sink at `T_(2)K`. The second engine receives heat rejected by the first engine and rejects to another sink at `T_(3)= 300K`. If work outputs of the two engines are equal, then find the value of `T_(2)`. |
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Answer» For the first engine, `Q_(1)-Q_(2)= W and (Q_(2))/(Q_(1))= (T_(2))/(T_(1))`….(i) For the second engine, `Q_(2)-Q_(3)= W and (Q_(3))/(Q_(2))=(T_(3))/(T_(2))`....(ii) `(Q_(3))/(Q_(2))xx(Q_(2))/(Q_(1))=(T_(2))/(T_(1))xx(T_(3))/(T_(2))` `(Q_(3))/(Q_(1))=(T_(3))/(T_(1))=(300)/(800)=3/8` Also, from (i) and (ii) `Q_(1)-Q_(2)= Q_(2)-Q_(3)` `Q_(1)+Q_(3)=2 Q_(2)` `1+(Q_(3))/(Q_(1))= 2(Q_(2))/(Q_(1))=(2T_(2))/(T_(1))` `1+3/8= (2T_(2))/(T_(1))= 11/8` `T_(2)= (11)/(16)xxT_(1)=(11)/(16)xx800= 550K` |
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