Question

How much work can be obtained from 100 calories of heat energy ?

• A. $100\,J$
• B. $420\,J$
• C. $42\,J$
• D. $4200\,J$

Answer 1

Answer: (B)

$420\,J$

Answer 2

$1$ calorie $= 4.2 \,J$ $\therefore$ Work done $=$ heat obtained in calories $\times 4.2\, J$ or $W= 100 \times 4.2 = 420\, J$