Question

How much work has to be performed to
produce 5 cal of heat ?
[mechanical equivalent of heat, J= 4.2 J/cal]
a) 20 J
b) 42 J
c) 21 J
d) 8.4 J​

Answer 1

Answer:

B) 42 J

Explanation:

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Answer 2

Answer:

C) 21 J

Explanation:

Work = heat * energy

1cal = 4.2 J

5 cal =?? J

5 cal = 5 * 4.2 J

= 21 J

21 J work has to be performed.

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