Question

What is electric power? Give its unit.

Answer 1

Electric power is the rate at which the work is done by the source ofe.m.f. in maintaining the current in electric circuit.

We know W = VIt joule

Power, P = \(\frac{W}{t}\) = \(\frac{VIt}{t}\)  joule/second

or P = VI

Unit of power is watt.

P = 1 watt if V = 1 volt and 1 = 1 ampere.

i.e., Power of an electric circuit is said 1 W if 1A of current flows in it against a P.D. of 1 volt.

Power is also measured in kW (= 1,000 W) and MW (= 106 W)

Answer 2

Electric power is the rate at which electric energy is transferred by an electric circuit. The SI unit of power is the watt, one joule per second.

P= work done per unit time =\(VQ/t\) = \(VI\)

where,
Q is electric charge in coulombs
t is time in seconds
I is electric current in amperes
V is electric potential or voltage in volts.