A refrigerator works between 4°C and 30°C. It is required to remove 600 calories of heat every second in order to keep the temperature of the refrigerated space constant. The power required is : (Take 1 cal = 4.2 Joules)
Answer & explanation
Correct answer: option 3
T1 = 303 K, T2 = 277 K
Coefficient of performance
β = \(\frac{Q_2}{W}\) = \(\frac{Q_2}{Q_1 - Q_2}\) = \(\frac{T_2}{T_1 - T_2}\) (Q1 = W + Q2)
\(\frac{Q_2}{W}\) = \(\frac{277}{26}\)
W = Q2 x \(\frac{26}{277}\) = \(\frac{600 × 4.2 × 26}{277}\)
W = 236.5 J