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Thermodynamics

Question
CBSEENPH11020824

Carnot engine having an efficiency of 1/10 as heat engine, is used as a refrigerator. If the work done on the system is 10 J, the amount of energy absorbed from the reservoir at lower temperature is

  • 1 J

  • 90 J

  • 99 J

  • 100 J

Solution

B.

90 J

straight beta space equals space fraction numerator 1 minus straight eta over denominator straight eta end fraction
equals space fraction numerator 1 minus begin display style 1 over 10 end style over denominator begin display style 1 over 10 end style end fraction space equals space fraction numerator begin display style 9 over 10 end style over denominator begin display style 1 over 10 end style end fraction
straight beta equals 9
straight beta equals straight Q subscript 2 over straight W
straight beta equals straight Q subscript 2 over straight W
straight Q space equals space 9 space straight x space 10 space equals space 90 space straight J