What is Electric Field? Definition, Formula, SI Unit, Types & Properties

An electric field is a field or space around an electrically charged object where any other electrically charged object will experience a force.

Electric field can be considered as an electric property associated with each point in the space where a charge is present in any form. An electric field is also described as the electric force per unit charge.

The formula of electric field is given as;



E -is the electric field.
F -is a force.
Q-is the charge.

Electric fields are usually caused by varying magnetic fields or electric charges. Electric field strength is measured in the SI unit volt per meter (V/m).

The direction of the field is taken as the direction of the force which is exerted on the positive charge. The electric field is radially outwards from positive charge and radially in towards negative point charge.

What is Electric Field?

The electric field is defined mathematically as a vector field that can be associated with each point in space, the force per unit charge exerted on a positive test charge at rest at that point.

The electric field is generated by the electric charge or by time-varying magnetic fields. In the case of atomic scale, the electric field is responsible for the attractive forces between the atomic nucleus and electrons which hold them together.

According to coulomb’s law, a particle with electric charge q1 at position x1 exerts a force on a particle with charge q0 at position x0 of,


r1,0 is the unit vector in the direction from point x1 to point x0

ε0 is the electric constant also known as absolute permittivity of free space C2m-2N-1

When the charges q0 and q1 have the same sign then the force is positive, the direction is away from other charges which means they repel each other. When the charges have unlike signs then the force is negative and the particles attract each other.

Electric field is force per unit charge,

Electric field can be found easily by using Gauss law which states that the total electric flux out of a closed surface is equal to the charge enclosed divided by the permittivity.

Types of an Electric Field

The electric field is mainly classified into two types. They are the uniform electric field and the nonuniform electric field.

1. Uniform Electric Field

When the electric field is constant at every point, then the field is called the uniform electric field. The constant field is obtained by placing the two conductor parallel to each other, and the potential difference between them remains same at every point.

2. Non-Uniform Electric Field

The field which is irregular at every point is called the non-uniform electric field. The non-uniform field has a different magnitude and directions.

Properties of an Electric Field

The following are the properties of an electric field.

  1. Field lines never intersect each other.
  2. They are perpendicular to the surface charge.
  3. The field is strong when the lines are close together, and it is weak when the field lines move apart from each other.
  4. The number of field lines is directly proportional to the magnitude of the charge.
  5. The electric field line starts from the positive charge and ends from negative charge.
  6. If the charge is single, then they start or end at infinity.
  7. The line curves are continuous in a charge-free region.

When the electric and magnetic field combines, they form the electromagnetic field.

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