We know about the definition of electric potential but that’s not it, there are many more things in this particular field. Well, not just that but there are many more derivations linked to this like ‘electric potential at the centre of a ring’ (sounds little tough but I’ll make it easy for you guys to understand).

**Electric potential at the centre of the ring is the same as the potential due to a point charge. Whereas the electric field is 0 at the centre of the ring because the electric field at the half side of the ring cancels out the other half.**

Before understanding **e**** lectric potential at the centre of a ring**, you need to understand

**e****and**

*lectric potential*

**e**

*lectric potential due to a point charge.*Table of Contents

## Proof of electric potential at the centre of the ring is the same as point charge:

**electric potential**first.

### What is electric potential ?

So before understanding **electric potential,** let’s understand the meaning of potential. *Potential is characteristic of a “ Location” and potential energy is the characteristic of a charged particle.*

*Electric potential*is the work done by an applied force on a unit charge bringing it from infinity to a specific point.

**.**

*The work done is called electric Potential*Electric potential to infinity is zero.

### Potential of a point:

Electric potential at point A

Potential |

So, here in the above image * VA represents the electrical potential* at

**point A**, this point

**A**can be anywhere.

*, we assumed that*

**to calculate this potential for point A***, now we don’t know how much far infinity is so we simply suppose the potential at infinity 0.*

**electric charge**has been brought from**infinity ‘ ∞’ to point A**

**e****where**

*lectric potential,***W**is the work done on bringing a point charge from infinity ‘ ∞’ to point

**A**and

**V**is the potential at a point.

Suppose we bring a charge from infinity to a point so we need some force to do that work in bringing a charge from infinity to a particular place and this energy or work which is done is what we call as **potential of a place**.

P.s: The term potential is a location-based characteristic. Every place has different potential. Just like one end of a battery has high potential and another end has low so that’s why when we connect both the sides of a battery with wire, current flows in the direction of higher potential.

**Now let’s define electric potential due to point charge:**

### Electric potential due to a point charge:

**. We will derive an expression of potential at that**

*brought from infinity to a point A***point A**due to

**source charge Q.**

**Q **is a charge and we have to find the potential at point **A** at distance **r. **

Electric potential due to a point charge diagram |

**P**at distance

**x**, here charge

**q**is been placed. So force on the test charge

**‘q**‘:

To move it to a** small distance ‘dx’** the work done is:

To work done :

*electric potential at the centre of a ring*.

### Electric potential at the centre of the ring:

Electric Potential at the centre of the charged ring |

Imagine a circular ring with radius **‘r’ and ϴ** is the angle between the **reference line ‘A’ to point on** the ring. **dӨ is the small angle** from a point on the surface. The length of line** A = radius of ring** (∵ line A is the reference line from the centre to surface)

To find the total potential to the ring at the centre we need to integrate the above equation.

*P.s:- ‘k’ in the above equation represents constant and ‘r’ represents the radius. *

This is the potential at the centre of the charged ring. We will notice that the equation of **e**** lectric potential** at the centre of the ring is the same as the

*electric potential due to a point charge*.

To understand the reason behind is, you can imagine that circular ring is nothing but will behave like a charge if we compare it to heavy bodies such as moon or earth. So that’s why* electric potential equation for point charge and at the centre of the ring is the same,*

Ring behaves as point charge due to which equation of potential difference is same for both of them

## Conclusion:

To understand the concept clearly, you will need to understand that *electric potential is the work done on bringing a unit charge from infinity to a point a*nd the electric potential difference is the difference between the potential of two points.

Electric potential at the centre of the ring is the same as that of electric potential due to a point charge.

### F.AQ:

**Q.1 Why electric field inside a ring is zero but the potential is not ****?**

Electric field is a vector quantity so it has magnitude as well as direction and due to this, electric field due to half ring is cancelled out by another half due to the opposite direction but electric potential is a scalar quantity due to which it doesn’t get cancelled out.

**Q.2 How is electric potential and potential difference not the same ?**

Electric potential is work done on a unit charge when bringing from infinity to a point. Whereas potential difference is the difference in electrical potential between two points.

**Q.3 What is potential ?**

Potential is the characteristic of a location.

**Q.4 What does ‘r’ refer to in the equation of electric potential due to point charge ?**

‘r’ is the distance between point and charge.