A freezer has an internal temperature of 0°C and is situated in a room with a steady temperature of 20°C. If the freezer is driven by an electric motor 0.5kW in power, calculate the time required to freeze 18kg of water already cooled to 0°C when placed in the freezer. Assume the freezer acts like an ideal heat engine in reverse. \ \

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Internal temperature of the freezer is $\"\"$ . \ \

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Steady temperature ofthe room is $\"\"$ .

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Freezer is driven by an electric motor $\"\"$ in power.

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Mass of the water placed in the freezer is $\"\"$ .

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Heat energy gained or lost by a substance is $\"\"$ .

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where $\"\"$ .

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$\"\"$ .

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Energy interms of power is $\"\"$ .

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Therefore, $\"\"$

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$\"\"$

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Substitute corresponding values in the expression.

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$\"\"$

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Time required to freeze 18 kg of water already cooled to $\"\"$ is 50.232 mins.

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