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Electric potential : Definition,formula and its meaning- Electrical Diary

What are Potential and Potential energy?

Potential is a word that is used to express the ability of a substance or person that can develop or perform better in the future. Potential is used in every field but as an Engineer, I have always seen and used this word in physics. If Something has potential that means it can do some useful work.

Electric Potential

Now we will move on to define What is Potential Energy?
if Energy is added with potential it means that We are talking about Physics. In Physics Potential Energy is defined as energy stored in a system due to its Position or Configuration. For Example, if a massive object of mass M kg is put on a wall of height H meter with respect to the ground then the Energy Store in the System of Object due to its position change is MgH and this Energy is called Potential Energy. Whenever this massive object will release from that height then it will do MgH amount of work.

What is Point Charge?

A point charge is a hypothetical charge which is situated in space and it has negligible dimension as compared to other charges or intensities which are situated around it in that space. In physics, We know that Electron is the smallest particle and it has negligible mass and its dimension is also very small then the electron is sometimes treated as a point charge. In reality, there is no existence of a point charge.

What is Electric Potential?

Electric Potential is defined as the amount of work done in bringing a positive unit charge from infinity to a given point in an electric field without producing acceleration. Electric Potential is a scalar quantity having unit Volt.

Explanation of Electric Potential

When the unit positive charge is brought from infinity to a given point in an electric field then this unit positive test charge experiences a force in the direction of the electric field and hence tries to go away from the influence of the electric field. To keep this positive unit charge in the Electric field external agent has to do some work against the movent of the unit charge to hold it in the electric field. Work is done by external agents to hold the unit charge in the electric field is stored in the system of unit charge and known as electric potential.

if w is the amount of work done by an external agent to bring a Q coulomb charge from infinity to a given point the Electric Potential is given as

V =W/Q

What is Electric Potential Difference?

The potential difference between two points is called electric potential. Let V1 is the Potential of a charge at a point and V2 be The potential at a different point. Then the potential difference between this two-point is calculated as  ∆V and is given as

∆V = V2 - V1 Volt

Unit of Potential Difference

As the potential difference is the difference of two-point potential then it has the same unit as that of electric potential i.e Volt.

What is Electrical Potential Energy?

As from the above wall mass system, When two or more electric charges are put in space then there is potential energy stored in their system due to their position with respect to each other. This potential energy is associated with the Charge system hence it is called Electric Potential Energy. Electrical Potential Energy associated with the charging system depends on the magnitude of the charge and its position.

Electrical Potential Energy Formula

Let Two charges having electric charges Q1 and Q2 are separated by a distance d. The Electric Potential Energy of these two charge systems is given as E and it is equal to
electric Potential
if the Unit of Charge is Coulomb and Distance d is in meter then the SI unit of Electrical Potential Energy will be Joule. Here Value of Constant term 1 / 4пεis equal to 9 x 109 N –m2/C2


If two charges of Q= 90 μC and Q2 =10μC are separated by a distance of 10 cm. Find their electric Potential Energy.


Q= 90 μC = 90 x10-6
Q2 =10μC =10 x10-6
d = 10 cm =10-1 m
Now from the above-given formula
E  = (9 x109 x 90 x10-6x 10 x10-6) /(10-1)
E = 81 x 10-1 joule
E =8.1 Joule. this is the electric Potential Energy of the Two Charge System

Also, Read

What is the quantization of charge?
What is 12V DC Motor?
What is armature reaction in DC Motor?

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