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How much heat is produced by a human body?(a) 200 W(b) 100 W(c) 50 W(d) 0.5 W |
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Answer» The correct choice is (b) 100 W For explanation: A man doing no or very little physical work needs about 2,000 kcal (or less) of energy in his daily food. The body converts this energy almost entirely into heat. 1 day = 24 x 60 x 60 s = 86,400 s 1 cal = 4.2 J Hence, 2000 kcal/day = 2000 × 4.2 kj/day = (frac{8.4 ,Mj}{86600s}) = 100 j/s = 100 W We see that a human body doing no work is equivalent to a heat source of about 100 W – the equivalent of a good bulb. |
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