Question

1 watt is equal to

• A. $J{s}^{-1}$
• B. $Js$
• C. $J{s}^{-2}$
• D. $J{s}^2$

Answer 1

The correct option is A

$J{s}^{-1}$

The explanation for the correct option:

Option A: $J{s}^{-1}$

1. Power is defined as the ratio of work done to the time spent in performing the work.
2. Mathematically we can see that , $\mathrm{Power}=\frac{W\mathrm{ork}\mathrm{done}\mathrm{or}\mathrm{energy}}{T\mathrm{ime}\mathrm{spent}}$
3. The unit of work done or energy is $J$ and the unit of time is $s$.
4. In terms of unit, it can be written as $\mathrm{P}=\frac{\mathrm{W}}{\mathrm{t}},or\mathrm{Watt}=\frac{\mathrm{Joule}}{\mathrm{second}}\Rightarrow \mathrm{W}=\frac{\mathrm{J}}{\mathrm{s}}=1{\mathrm{Js}}^{-1}$

Thus, $1watt$ is equal to $1J{s}^{-1}$

Hence, Option (A) is correct.