Question

A refrigerator works between $4^{\circ}C$ and $30^{\circ}C$. 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 : $(Take\, 1 \,cal\, =\, 4.2 \,Joules)$

• A. 23.65 W
• B. 236.5 W
• C. 2365 W
• D. 2.365 W

Answer 1

Answer: (B)

236.5 W

Answer 2

$\beta = \frac{Q_2}{W} = \frac{T_2}{T_1 - T_2}$ (Where $Q_2$ is heat removed)
$\Rightarrow \, \frac{600 \times 4.2}{W} = \frac{277}{303 - 277}$
$\Rightarrow \, W = 236.5$ joule
$\Rightarrow \, { Power = \frac{W}{t} = \frac{236.5 \,joule}{1 sec} = 236.5 \, watt.}$