 Solution

ID: past-exam-of-the-short-options-paper-of-the-physics-prelims-of-the-university-of-oxford/2021/s03/1/f/solution

If the temperatures, exposed area, and surroundings remain fixed, the net radiated energy over one day is

E = P_{net} (86400 s) ≃ 1.60 \times 1 0^{7} J .

Using the supplied conversion gives

E ≃ 3.82 \times 1 0^{6} cal = 3.82 \times 1 0^{3} kcal .

A dietary Calorie is one kilocalorie, so the result is about 3820 dietary Calories, rather than 3.82 million dietary Calories.

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