Question

Work done can be converted from joules to calories by

• A. dividing by $J$
• B. subtracting $J$
• C. multiplying by $J$
• D. adding $J$

Answer 1

The correct option is A

dividing by $J$

Step 1:Explanation

We know that calories and joules (J) are related as

$1cal=4.184J$.

1. So, a calorie is 4.184 times a bigger unit than J.
2. Therefore, to convert work done from joules to calories, we must make the magnitude of the work done smaller by 4.184 times.
3. Then new magnitude thus obtained represents work done in calories.

$$\begin{gathered} 1cal=4.184J \\ or \\ 4.184J=1cal \\ \Rightarrow 1J=\frac{1}{4.184}cal \end{gathered}$$

This denotes that when work done calculated in joules is divided by 4.184, we get the value of the same work done in calories..

Hence, A) is the correct option.