Question

The unit of power in terms of unit of energy is ____.

Answer 1

Hint: Convert the mathematical formula of power into base units in the MKS system.

Complete answer:
The international System of units (SI) is the modern form of the metric system. It is the only system of measurement with official status in nearly every country in the world. It comprises a coherent system of units of measurement starting with seven base units. And the other units which are defined in terms of seven base units are called derived units.
The seven base units are as follows –

Symbol	Name	Quantity
s	Second	Time
m	metre	Length
kg	kilogram	mass
A	ampere	Electric current
K	kelvin	Thermodynamic temperature
mol	mole	Amount of substance
cd	candela	Luminous intensity

Power is a derived quantity. Power is defined as energy transferred or converted per unit time.
$P=\dfrac{E}{t}$
The SI unit of energy (E) is J. So the dimension of power is $\dfrac{J}{s}$ and $\dfrac{J}{s}$ is known as Watt. Hence, the unit of power in terms of units of energy is Joule/Second .

Additional Information:
The MKS unit of power can be derived with the help of base units.
$\begin{align}
  & P=\dfrac{E}{t} \\
 & E=F\times d \\
 & E=kgm{{s}^{-2}}m=kg{{m}^{2}}{{s}^{-2}} \\
 & P=\dfrac{kg{{m}^{2}}{{s}^{-2}}}{s}=kg{{m}^{2}}{{s}^{-3}} \\
\end{align}$

Note:
It is very difficult to learn SI units of all the quantities. So students should learn the formula of all the quantities. And only remember the SI units of base units and some important physical quantities like force, energy etc.