Question

What is electric power? Write the essential formula for it.

Answer 1

Hint: In electricity, when current flows in the wire and provides electric current due to movement of electrons and hence developing potential difference across two points in electric circuits, then the work done by these moving charges is known as electrical energy consumed in an electric circuit.

Complete step by step answer:
Let us first understand the definition of electric power. Electric power is defined as the rate of electrical energy consumed each second or Electric power simply is the ratio of electrical energy and time for which that amount of electrical energy is consumed.

Since, energy is measured in the units of Joules and time is measured in units of seconds so, Power will be written mathematically as $P = \dfrac{E}{t}$ which will have the units of $\,Joule\,{\sec ^{ - 1}}$ and it’s denoted by $1\,Joule\,{\sec ^{ - 1}} = 1Watt$ .
The other most common formulas of power in terms of current resistance and potential difference are written as
$P = {I^2}R$ Where I is the current flowing in the wire having resistance of $R$. The units of power, may be written here as ${A^2}\Omega $
$P = \dfrac{{{V^2}}}{R}$
Where $V$ is the potential difference between two points and has a resistance of $R$.
The most general Units of power in large electrical circuits such as the electricity which is supplied at homes are used as $kW$ kilowatts and $MW$ Megawatts.

Note: It should be remembered that, the other two formulas of power are simple derived from the basic formula of power which is $P = V \times I$ and by ohm’s law we know $V = RI$ and the units of conversions of power areas $1kW = {10^3}Watts$ and $1MW = {10^6}Watts$.