Which of the following represents electrical power dissipated in an electrical circuit?
I2R
VI
V2R
Electrical power, P can be defined as the rate at which electrical energy (W) is consumed in an electrical circuit.
⇒P=Wt
Potential difference, V across any circuit is defined as the electrical energy W supplied by a source for a unit flow of charge (I×t)
∴V=WI×t
⇒W=V×I×t
So, power, P=V×I×tt=VI
By Ohm's law, V=IR or I=VR
Substituting the value of I in the expression of power, P=VI=V×VR=V2R
Since, V=IR, P=V2R=(IR)2R=I2R
Thus, electrical power P dissipated in a resistor =Wt=VI=V2R=I2R.