What is Electrical Power?

Electric Power is the electrical energy supplied to an electric circuit per unit time or, the rate at which the work is being done in an electrical circuit is called electric power. The source of this power is the cell or battery. The SI unit of power is watt or joule per second.

Consider an electrical circuit with resistance R and potential difference V. A current I flows through the circuit. Consider a time interval t. In this time interval, some charge Q must flow through the circuit. The work done in moving the charge Q through a potential difference V is VQ.

Work done =VQ

Electric power is the rate of electric work done per unit time.

Power = $\frac{VQ}{t}$

Power = VI (since I = $\frac{Q}{t}$)