A real engine has an efficiency of 33%. The engine has a work output of 24 j per cycle (a) How much hear energy is extracted from the high temperature reservoir per cycle(A) 8 J(B) 16 J(C) 48 J(D)72 J(E) the question can be answered only if theengine is a carnot engine.(b) How much heat energy is discharged into the low temperature reservoir per cycle?(A) 8 J(B) 16 J(C) 48 J(D) 72 J(E) the question can be answered only if the engine is a carnot engine.(c) For this engine TL = 27ºC. What can be concluded about TH? (A) TH= 450ºC(B)TH=177ºC.(C) TH > 177ºC.(D)TH(E) 177ºC H
Simran Bhatia , 9 Years ago
Grade 11
4 Answers
Aditi Chauhan
Last Activity: 9 Years ago
(a) The correct option is (D) 72 J. The efficiency ε of a Carnot engine is defined as,
Urjita Sharma
Last Activity: 8 Years ago
As the formula of efficiency is only applicable to Carnot engines and as this is a real engine the first two questions cannot be answered. Thus option E for both.If it were a Carnot`s engine, then TH would have been 177°C . Considering a Carnot`s engine having The as 177 C would give efficiency of 33% but as this is a real engine its efficiency must be less than 33%. Hence if it is 33% then it`s TH must be greater than 177°C.
Urjita Sharma
Last Activity: 8 Years ago
The answer for first two can be given by the formula e= W/Qh1/3= 24/QhQh=72J1/3=1-Ql/QhQl= 48JPardon my previous answer was wrong.The third part is pretty much fine.
Urjita Sharma
Last Activity: 8 Years ago
For the third part, if the efficiency is less than a Carnot`s engine, for a Carnot`s engine its The would be 177C e=W/Qh Qh proportional to Th hence e is inversely proportional to Th thus as e is less than will be more than 177C
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