question_answer

A Carnot engine having a perfect gas as the working substance is driven backward and is used for freezing water already at\[0{}^\circ C\]. If the engine is driven by a 500 W electric motor having a efficiency of 60 %, how long (in seconds) will it take to freeze 15 kg of water. Take \[15{}^\circ C\]and \[0{}^\circ C\] as the working temperatures of the engine and assume there are no heat losses in the refrigerating system. Latent heat of ice \[=333\times {{10}^{3}}J/kg.\]

Answer:

914.8