In a cold storage,ice melts at the rate of 2 | vedclass

Name: Exam Paper Generator | JEE NEET Paper Generator | Vedclass
Brand: Vedclass
Rating: 5 (35 reviews)

Question

(B) The rate of heat entering the cold storage is $Q_2 = \frac{mL}{t} = \frac{2 	imes 10^3 \ g 	imes 80 \ cal/g}{3600 \ s} = \frac{160000}{3600} \ c

Vedclass · Accepted Answer

$13.6$

Vedclass · Answer

(B) The rate of heat entering the cold storage is $Q_2 = \frac{mL}{t} = \frac{2 	imes 10^3 \ g 	imes 80 \ cal/g}{3600 \ s} = \frac{160000}{3600} \ cal/s = \frac{400}{9} \ cal/s$.Converting to Joules per second (Watts): $Q_2 = \frac{400}{9} 	imes 4.2 \ J/s = 186.67 \ W$.The coefficient of performance $(COP)$ of a Carnot refrigerator is given by $	ext{COP} = \frac{T_2}{T_1 - T_2} = \frac{Q_2}{W}$.Here,$T_2 = 0^{\circ} C = 273 \ K$ and $T_1 = 20^{\circ} C = 293 \ K$.So,$\frac{273}{293 - 273} = \frac{186.67}{W}$.$\frac{273}{20} = \frac{186.67}{W}$.$W = \frac{186.67 	imes 20}{273} \approx 13.67 \ W$.Thus,the minimum power output is approximately $13.6 \ W$.

In a cold storage,ice melts at the rate of $2 \ kg$ per hour when the external temperature is $20^{\circ} C$. The minimum power output of the motor used to drive the refrigerator which just prevents the ice from melting is (latent heat of fusion of ice $= 80 \ cal \ g^{-1}$) (in $W$)

Similar Questions

Freezing compartment of a refrigerator is at $0^{\circ} C$ and room temperature is $27.3^{\circ} C$. Work done by the refrigerator to freeze $1 \ g$ of water at $0^{\circ} C$ is $(L_{\text{ice}} = 80 \ cal \ g^{-1})$. (in $J$)

$A$ Carnot engine,having an efficiency of $\eta = 1/10$ as a heat engine,is used as a refrigerator. If the work done on the system is $10 \ J$,the amount of energy absorbed from the reservoir at a lower temperature is ....... $J$.

If the door of a refrigerator is kept open in a closed room,will the room become cooler or warmer?

Determine the coefficient of performance for the given temperature limits.
$T_{1} = 27^{\circ}C$ [outside fridge]
$T_{2} = -23^{\circ}C$ [inside fridge]

An ideal heat engine has an efficiency $\eta$. The coefficient of performance of the engine when driven backward will be

Vedclass Test Series

Exam Paper Generator

Online Exam Module