State the formula for electric power. Hence, obtain its SI unit.

Explanation

Electric power (P)= `("electric work (W) done or electric energy used")/("time (t)")`
The SI unit of work is the joule and that of time is the second. Hence, the SI unit of power is the joule per second. It is given the special name : the watt (W) . One watt equals one joule per second.
`W=VIt = I^(2)Rt=(V^(2))/(R)t " " therefore P=W//t=VI = I^(2)R=V^(2)//R`
Here, V is the potenital difference applied across an electrical appliance , R is the resistance of the appliance and I is the current through the appliance.