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Given, efficiency of engine, η = 1/10.

1. Work done on system W = 10 J
2. Coefficient of performance of refrigerator β = Q2/W = (1 − η)/η = 9
3. Energy absorbed from reservoir Q2 = βW = 9 × 10 = 90 J
4. A refrigerator works along the reverse direction of a heat engine.

Correct answer: Coefficient of performance of refrigerator β = Q2/W = (1 − η)/η = 9

Solution

The coefficient of performance (β) of a refrigerator is given by β = (1 − η)/η. Substituting η = 1/10, we get β = (1 − 1/10)/(1/10) = 9. This matches option B.

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