Chapter 22, Problem 75A

To determine

To Define: The unit of power in terms of fundamental SI units.

Answer to Problem 75A

  $1\text{W}=1\text{J/s}$

Explanation of Solution

Introduction:

The electric power $\left(P\right)$ across a circuit is given by,

  $P=\frac{\text{Energy}}{\text{time}}$

It is known that the SI unit of Energy is Joules (J) and that of time is seconds (s). Then, the SI unit of power can be written as,

  $\begin{array}{l}1\text{W}=\frac{\text{1 J}}{1\text{s}}\\ 1\text{W}=1\text{J/s}\end{array}$

Conclusion:

Hence, the unit of power in terms of SI units is $1\text{J/s}$ .