Electric Power - Definition, Formula, Unit, FAQs

What is Electric Power?

Power is often defined as the degree to which a task is performed. When this is done in relation to time and the electrical circuit, it is known as electric power. Similarly, electrical energy is defined as the rate at which electricity is transferred across the electrical circuit at each time point. Electric Power is versatile - it can be generated by generators in our homes and can be supplied with batteries used in devices. Electric Power in an electric circuit is the rate at which work is done or energy is transformed into an electrical circuit.

JEE Main 2025: Physics Formula | Study Materials | High Scoring Topics | Preparation Guide

JEE Main 2025: Syllabus | Sample Papers | Mock Tests | PYQs | Study Plan 100 Days

NEET 2025: Syllabus | High Scoring Topics | PYQs

Electricity Unit of Electric Power

When you press or pull something at a certain level, you do a certain job, and are represented by Joule in physics. Strength is actually a measure when performing any task. Watt is a unit of Electric Power. It is the degree to which a task is performed or how quickly a task is performed. One Watt is one Joule of work done on an object per second. Watt is represented as W.

The voltage is an electromotive force or a potential difference between two points, indicating the amount of work required to move the charge between two points. The unit of Electric Power is Watt.

The energy consumed in an electrical circuit is called one Watt where one current ampere appears to flow in that electrical circuit. In this case, the potential difference of 1 volt is used throughout.

If you want to identify a large unit of Electric Power of electricity, you can use a kilowatt (equivalent to 1000 watts).

Also read -

• NCERT Solutions for Class 11 Physics
• NCERT Solutions for Class 12 Physics
• NCERT Solutions for All Subjects

What is Electrical Power? Write its unit.

Electric Power formula,

To calculate the power, the simplest equation is the work done is divided by time.

(1) P = W / t

W done work; time

However, the above is mainly used for mechanical power. In terms of electricity, another equation is used when calculating a function by the amount of the charge and the potential difference where the charge goes.

(2) W = qV

When q = total value used and V = voltage

When we substitute (1) in (2) we get

(3) P = qV / t

Also read :

• NCERT solutions for Class 12 Physics Chapter 3 Current Electricity
• NCERT Exemplar Class 12 Physics Solutions Chapter 3 Current Electricity

Additionally, we know that the current is charged per second passing through the region at any point in time.

(4) q = It

Where q = total value and I = current (ampere)

Now, when we substitute (4) in (3)

P = IV

Here, P power, V or voltage difference may be present in the circuit and I is Current.

Power can also be written as

P = V^2 / R or I^2R

When V is voltage, R is resistant, and I is current..

This can be achieved by applying Ohm's law, which states that Voltage is equal to current*resistance.

Power Strength Formula

As power consumption level, power can be directly calculated using

P = Et

Where,

E is energy (Joules)

t is time in seconds

NCERT Physics Notes:

• NCERT Notes Class 11th Physics
• NCERT Notes Class 12th Physics
• NCERT Notes For All Subjects

P = VQt

Where,

Q charges (Coulombs)

V is the potential difference in volts

t time in seconds

Energy Problems and Answers

The power used by the metal for two minutes is 18 kJ, at a power of 250 volts. Calculate Electric Current.

Here, t = 120 seconds

Energy = 18 kJ = 18000 Joules

Power = 250 V

Electricity = P = W / t = 18000 Joule / 120 seconds = 150 Watt

Hence,here Electric current (I) = 150/250

= 0.60 Ampere

Also check-

• NCERT Exemplar Class 11th Physics Solutions
• NCERT Exemplar Class 12th Physics Solutions
• NCERT Exemplar Solutions for All Subjects