In this article, I will teach you the concept of **electric potential** and **potential difference**. Electric potential and potential difference are two of the most important terms in electric circuits. Electric potential is the amount of potential energy stored in a charged body. Whereas, potential difference, also called** voltage**, is the difference of electric potentials of two charged bodies.

Let us start our journey of exploring electric potential and potential difference with the basic introduction to electric potential.

## What is Electric Potential?

**Electric potential** can be defined as the ability of a charged body to do work.

Therefore, if a body has a greater capacity to do work, it has high electric potential.

When some work is done on a body. The work done is stored in the body in the form of potential energy. Due to this potential energy, the body gains the ability to do some work. When a body has some stored potential energy, then it is considered a charged body.

Every charged body has the ability to do work due to the stored potential energy. This ability to do work is termed as electric potential of the body.

Mathematically, the electric potential of a charged body is measured as the work done per unit charge i.e.,

$$\text{Electric Potential}=\frac{\text{Workdone }(W)}{\text{Charge} (Q)}$$

Hence, the electric potential can be defined as the amount of work done (W) required to charge a body to a charge Q. This work done is stored as the potential energy in the body.

**Unit of Electric Potential**

From the above formula, we can derive the unit of electric potential as,

$$\text{Unit of Electric Potential}=\frac{\text{Joule}(J)}{\text{Coulomb} (C)}$$

Hence, the unit of electric potential is **Joule per Coulomb (J/C)**.

Also,

$$1 J/C = 1 \text{Volt} (V)$$

Where, **Volt (V)** is the SI unit of electric potential.

Let us now understand the exact meaning of “*x* Volts” electric potential on a body.

When we say that a charged body has an electric potential of 10 Volts, it means that we are required to do a work of 10 joules to charge the body to 1 coulomb of charge.

Therefore, the greater the work done required to charge a body to unit charge, the greater its electric potential.

Hence, this is all about the concept of electric potential. Let us now discuss the concept of potential difference or voltage.

## What is the Potential Difference?

The **potential difference**, also called **voltage**, is defined as the difference in the electric potentials of two charged bodies.

In an electric circuit, the potential difference can be defined as the difference of electric potentials between two points or nodes.

Let us consider an electric circuit shown below.

Consider two points A and B in the circuit having electric potentials of 7 V and 5 V. Then, the potential difference between these two points will be,

V_{AB} = 7 – 5 = 2 V

This is how the potential difference or voltage between two points is calculated.

**SI Unit of Potential Difference**

Since the potential difference is nothing but the difference of electric potentials. Hence, it is also measured in Volts (V).

In an electric circuit, the voltage between two points (say A and B) is said to be 1 volt if we have to do a work of 1 joule to move a unit charge (1 C) from one point to another.

**Important Points About Voltage**

- In an electric circuit, the voltage or potential difference is always specified across two points. There is no such thing as a voltage at a single point.
- Sometimes, we have given a single point. In that case, we consider the ground or common terminal as the reference point to specify the voltage.
- In an electric circuit, if we have two points of the same potentials. Then, no current will flow between those two points. Therefore, for the flow of current between two points in a circuit, a potential difference must be there.

## Potential Rise and Potential Drop

The concept of potential rise and potential drop is very important in circuit analysis.

In an electric circuit, when the direction of current through an element is such that it flows from a point of lower potential (denoted as -ve sign) to the point of higher potential (denoted by +ve sign), then there is an increase in potential across the element. It is termed a **potential rise**.

In simple words, when current through an element flows from the negative terminal to the positive terminal. Then, there is a rise in potential across the element.

On the other hand, when the electric current through an element flows from the positive terminal (point of higher potential) to the negative terminal (point of lower potential), then there is a decrease in the potential across the element. Hence, it is called the **potential drop**.

In this circuit, the current through the battery flows from the negative terminal to the positive terminal. Hence, there is a potential rise across the battery. Whereas, the current through the resistor is flowing from the positive terminal to the negative terminal. Hence, there is a potential drop across the resistor.

Hence, this is all about the potential difference or voltage in an electric circuit.

Let us now discuss some solved numerical examples on the basis of electric potential and potential difference.

## Examples based on Electric Potential and Voltage

**Numerical Example (1)** – Calculate the electric potential of a body, if it requires a work done of 500 joules to attain a charge of 3 coulombs.

**Solution** – Given data,

Work done (W) = 500 J

Charge (Q) = 3 C

Then, the electric potential of the body will be,

$$V=\frac{W}{Q}=\frac{500}{3}$$

∴ V = 166.67 Volts

**Numerical Example (2)** – What will be the potential difference across a resistor? If a work of 150 joules is to be done in moving a charge of 5 coulombs from one end of the resistor to another.

**Solution** – Given data,

Work done (W) = 150 J

Charge (Q) = 5 C

The potential difference across the resistor will be,

$$V=\frac{W}{Q}=\frac{150}{5}$$

∴ V = 30 Volts

## Conclusion

In conclusion, an electric potential is the amount of work required to charge a body to a unit charge. Whereas, the potential difference is the difference of potentials of two points in a circuit. In this article, I have explained the concepts of electric potential and potential difference (voltage) in detail. I have also included two solved numerical examples based on potential and potential difference.

If you have any queries related to this topic, please let me know in the comment section. I will answer shortly.