Difference between Electrical Energy and Electrical Power?

What is Electrical Power?

The rate at which work is completed is frequently referred to as power. Electric power is what happens when this is done in relation to time in an electrical circuit. Electric power, on the other hand, is defined as the rate of electric energy transfer over an electrical circuit per unit of time. Electric power is adaptable in that it can be generated in our homes and delivered to electric batteries in equipment.

The S.I unit of electrical power is Watt (W) or Joule/Sec (J/s).

Electrical PowerFormula

To find the value of electrical power, the easiest way is work done (W) divided by time (t)

P = W/t ------------ (1)


W is work done

t is time

The above equation is mainly used to find the mechanical power when we calculate work based on the amount of charge and the potential difference that the charge is traveling through.

W = qV --------------------- (2)

Where q = total charge used

V = voltage

When we apply equation (1) in equation (2),

P = qV/t -----------------(3)

The charge per second that flows through the circuit at any one time is known as current.

q = It -------------------- (4)

Where q = total charge

I = current (ampere)

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

P = VI -------------------(5)

Here, P is the power, V or voltage is the potential difference in the circuit,

I is the electric current.

Power can also be written as

P = V2/R or I2R

Where V is the voltage,

R is the resistance,

I is the electric current.

When we use the Ohms law, which states that electric current is proportional to voltage and inversely proportional to resistance, we can get these results.

Types of electrical power

Electrical power mainly classified into three. They are

  • Active power
  • Reactive power
  • Apparent power.

What is Electrical Energy?

The capacity to perform electrical work is defined as electrical energy. Moving electric charges provide electrical energy, which is a type of kinetic energy.

The amount of energy relies on the charge’s speed; the faster it moves, the more electrical energy it carries.

Electrical energy is potential energy or energy held in an object as a result of its position. In terms of electrical energy, the object is a charged particle, and the position is where that charged particle is in relation to the electric field. Due to the force of the electric field, the charged particle will have the ability to move or do work.

The S.I unit of electrical energy is Watt.Sec (Ws) or Joule (J)

Electrical Energy Formula

E = QV

Where, Q is the charge

V is the potential difference

A cell has a positive terminal and a negative terminal.

The negative terminal has more electrons than the positive terminal, while the positive terminal has fewer electrons. Assume A is the positive terminal, and V(A) is the electrical potential at A. Similarly, B represents the negative terminal, and V(B) is the electrical potential at B. Electric current flows from point A to point B, therefore V(A) > V(B)

The potential difference between A and B is measured by

V = V(A) – V(B) > 0

The rate of charge flow through the cross-section of a conductor is defined as an electric current.

Thus, it is given by I = ∆Q/ ∆t

where I is the electric current

∆Q is the quantity of electric charge flowing through a point in time ∆t.

Types of electrical Energy

  • Static electricity
  • Current electricity

Power Vs Energy

S.No Electrical power Electrical Energy
1 Electrical power is defined as the ‘rate of work done per unit charge’ or ‘rate of energy transfer per unit time’. Electrical energy is defined as the ability to do electric work
2 Power, §= (Work/Time) or (Energy/Time) Energy, (W)= (WorkTime) or (EnergyTime)
3 Electrical power is denoted by the letter P. Electrical energy is denoted by the W or E.
4 The S.I unit of electrical power is Watt (W) or Joule/Sec (J/s). The S.I unit of electrical energy is Watt.Sec (Ws) or Joule (J).
5 Can’t convert it into another form of energy. It can easily convert it into another form of energy such as heat, light, etc.
6 Can’t generate Electrical power like Electrical energy Electrical energy can be generated or can be consumed.
7 Can’t store power Can easily store

Example of Electrical Energy Here are some examples of electrical energy:

  • A chemical reaction occurs in a car battery, resulting in the production of an electron with enough energy to move in an electric current. The circuits in the automobile receive electrical energy from these moving charges.
  • Lightning is an example of electrical energy that occurs during a thunderstorm; what we perceive as lightning is nothing more than electricity discharging in the atmosphere.

Example of Electrical Power

Examples of electrical power are

A rechargeable battery- it will act as a power source when we connected the battery to a load and it will act as a load while we connected it to the battery charger.

Home appliances like bulb, electric motor and heater