Question

One joule is approximately equal to:

• A. $0.28cal$
• B. $0.32cal$
• C. $0.24cal$
• D. $4.2cal$

Answer 1

The correct option is C

$0.24cal$

Step 1: Given

To find the value of one joule in calories.

Step 2: Formula Used

One joule is the SI unit of energy that measures the amount of energy spent in moving a force of one newton by a distance of one meter.

One calorie is the unit of heat energy required to raise the temperature of one gram of water by one degree Celsius. And $1cal=4.2joules$.

Step 3: Solution

Find the value of one joule in terms of calories.

$$\begin{gathered} 4.2J=1cal \\ \Rightarrow 1J=\frac{1}{4.2}cal \\ \Rightarrow 1J\approx 0.24cal \end{gathered}$$

Hence, option C is correct.