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The power input in a circuit P can be expressed in terms of voltage V and current I in the circuit as follows:
P=V/I
P=V2/I
P=VI
P=V2I
P=VI
The electrical power P dissipated or consumed in an electrical circuit is defined as the product of the potential difference V (voltage) and the electric current I flowing through that circuit. This fundamental relationship is derived from the definition of power as the rate of work done or energy transformed per unit time.
The electrical power P dissipated or consumed in an electrical circuit is defined as the product of the potential difference V (voltage) and the electric current I flowing through that circuit. This fundamental relationship is derived from the definition of power as the rate of work done or energy transformed per unit time.
Think of it like a water pipe: the power (work done) depends on both the water pressure (voltage) and how much water flows through the pipe per second (current).
P-VI (pronounced 'Peewee'): Power = Voltage ├Ч Current.
P=VI тАФ Fundamental power formula
P=I2R тАФ Power in terms of current and resistance (using Ohm's Law)
P=RV2тАЛ тАФ Power in terms of voltage and resistance (using Ohm's Law)
Since electric power P is the rate of energy transfer, it is calculated as P=tWтАЛ. Because work W done to move a charge q across a potential difference V is W=Vq, and current I is the flow of charge per time (I=tqтАЛ), substituting these gives P=V├Ч(tqтАЛ)=VI. This law holds true for DC circuits and for instantaneous power in AC circuits.
The SI unit of electric power is the Watt (W), equivalent to 1 Joule per second.
This relationship is universal for all resistive elements in a circuit.
For AC circuits, P=VIcos╧Х, where cos╧Х is the power factor.
Allows easy calculation of energy consumption in appliances.
Does not account for reactive power in AC circuits without the power factor.
Calculating wattage ratings for household electrical appliances.
Determining the capacity requirements for circuit breakers and wiring.
Option A (P=IVтАЛ) represents resistance (R) by Ohm's Law.
Option B (P=IV2тАЛ) is dimensionally incorrect for power.
Option D (P=V2I) is dimensionally incorrect.
C is correct тАФ The standard formula for electric power P is the product of voltage V and current I, expressed as P=VI.
Remember that Ohm's Law (V=IR) allows you to transform the P=VI formula into P=I2R or P=RV2тАЛ depending on which variables are known in your problem.
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