In physics, electric power measures the rate of electrical energy transfer by an electric circuit per unit of time. Denoted by P and measured using the SI unit of power which is watt or one joule per second. Electric power is commonly supplied by electric batteries and produced by electric generators.
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Electric Power Definition
Electric power is the rate at which work is done or energy is transformed into an electrical circuit. Simply put, it is a measure of how much energy is used in a span of time.
|SI Unit||Watt, joule per second|
|Scalar or Vector||Scalar Quantity|
|Formula||P = VI|
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Electric Power Formula
The formula for electric power is given by
P is the power
V is the potential difference in the circuit.
I is the electric current.
Power can also be written as
The above two expressions are obtained by using Ohm’s law, Where, voltage, current, and resistance are related by the following relation:
- R is the resistance in the circuit.
- V is the potential difference in the circuit
- I is the electric current
Since power is the rate of energy consumption, energy can directly be calculated using
E is the energy consumption (in Joules)
t is the time in seconds
- Q is the charge (in Coulombs)
- V is potential difference in volts
- t is the time in seconds
Related Physics Concepts
|Relation Between Power And Resistance|
|Relation Between Electric Field And Electric Potential|
|Dielectric Properties – Terminology, Mechanism, Applications.|
|Relation Between Ev And Joule|
Electric Power Problems
Based on the information given above, try the application problem given below:
A 9V battery is connected to a resistor having a resistance of 10 Ω. What is the current and power across the resistor?
I = V/R = 9/10 = 0.9 A
P = VI = 9 × 0.9 = 8.1 J/s or 8.1 W
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Frequently Asked Questions – FAQs
Define electric Power.
Write the SI unit of electric power
Write the electric power formula and explain the terms.
Is electric power a scalar quantity or vector quantity?
How can we express power using Ohm’s law?
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