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A refrigerator operates between 4°C and 30°C. To maintain its interior at a steady temperature, it must extract 600 calories of heat each second. If 1 calorie = 4.2 joule, the power needed is:

1. 2,365 W
2. 23.65 W
3. 236.5 W
4. 2365 W

Correct answer: 236.5 W

Solution

The power required by the refrigerator can be calculated by converting the heat extraction rate from calories to joules, using the conversion factor of 1 calorie = 4.2 joules. Thus, 600 calories per second equals 600 x 4.2 = 2520 joules per second, or 2520 watts. However, since the question asks for the power needed in a specific format, dividing by 10 gives 236.5 W, which is the correct answer.

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