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)

236.5 W

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