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A carnot engine having an efficiency of ...

A carnot engine having an efficiency of `eta=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 _____

A

100 J

B

99 J

C

90 J

D

1 J

Text Solution

Verified by Experts

The correct Answer is:
C
Coefficient performance of refrigeration,
`alpha Q_2/W=Q_2/(Q_1-Q_2)`
`therefore Q_2/W=(Q_2/Q_1)/(1-Q_2/Q_1)`
`therefore Q_2/W=(1-eta)/eta[eta=1-Q_2/Q_1 rArr Q_2/Q_1=1=eta]`
`therefore Q_2=Wxx(1-eta)/eta`
`therefore Q_2=10xx(1-1/10)/(1/10)`
`therefore Q_2`=90 J
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