A heat engine employing a carnot cycle with an efficiency of `eta = 10 %` is used as a refrigerating machine, the thermal reservoirts being the same. Find its refrigerating efficiency `epsilon`.

Explanation

Used as a refrigerator, the refrigerating efficiency of a heat engine is given by
`epsilon = (Q'_2)/(A) = (Q'_2)/(Q_1 - Q_2) = (Q'_2//Q_1)/(1 - (Q_2')/(Q_1)) = (1 - eta)/(eta) = 9 here`
where `eta` is the efficiency of the heat engine.
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