# Electric field - Definition, Formula, SI Unit

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## What is Electric field ?

An electric field is a physical phenomenon that arises due to the presence of electric charges. Electric charges generate an electric field in the space surrounding them, which exerts a force on other electric charges within the field

Mathematically, the electric field is defined as the force per unit charge experienced by a test charge placed at a given point in space. The electric field is a vector field, meaning that it has both magnitude and direction.

## Definition of Electric field

An electric field is the area around an electrically charged object where its influence can be felt. It is a region of space where a force is exerted on any electrically charged object placed within the field.

If a positive charge is placed within an electric field, it will experience a force in the direction of the field, while a negative charge will experience a force in the opposite direction. The strength of the electric field is proportional to the amount of charge creating it and inversely proportional to the distance from the charged object.

## SI Unit of Electric field

The SI unit of the electric field is Newtons per Coulomb (N/C). The direction of the electric field is defined as the direction in which a positive test charge would move if placed at the given point.

## Formula of Electric field

The formula for calculating the electric field at a given point in space is:

### E = F / q

where,  E is the electric field in Newtons per Coulomb (N/C), F is the force in Newtons (N), and q is the charge in Coulombs (C).

This formula relates the electric field strength to the force that would be exerted on a test charge of magnitude q placed at the given point in space. The electric field vector is defined as the force per unit charge, and its direction is given by the direction of the force on a positive test charge.

For a point charge q located a distance r from the point of interest, the electric field at that point is given by:

### E = k * q / r^2

where k is Coulomb's constant (k = 9 x 10^9 Nm^2/C^2). This equation gives the magnitude of the electric field created by a point charge, with the direction of the field given by the direction of the force on a positive test charge placed at the given point.

## Solved Examples

Q.1 A force of 10 N is acting on the charge 5 Î¼ C at any point. Determine the electric field intensity at that point.

Solution

Given, Force F = 10N

Charge q = 5mu*C

Electric field formula is given by

E=F/q

E= 10N / 5 * 10 ^ - 6 * C

E = 2.0 * 10 ^ 6 * N / C

## Uses of Electric field

The electric field is an important concept in physics and is used in a variety of applications, including electrical engineering, electronics, and particle physics. Understanding the behaviour of electric fields is essential to understanding the behaviour of electric charges and their interactions with each other.

The electric field is a fundamental concept in physics and is used to explain many phenomena, such as the behaviour of electric motors, the flow of electricity through wires, and the behaviour of subatomic particles.