Electric Field Intensity

Electrically charged particles generate a force field surrounding them. A physical field exists there. If there are any additional charged particles in the space surrounding the electric field, the electric particles will put force on those additional charged particles. It is possible for this energy to be either attractive or repellent. Electric field intensity, commonly referred to as electric field strength or just electric field, is a basic concept that helps understand the activities and interactions of electric charges.

Table of Contents

What is electric field intensity?
Properties of electric field
Electric field intensity due to a point charge
Practice problems
FAQs

What is Electric Field Intensity?

Electric field intensity can be defined as the force that is experienced by a positive test charge set at a specific location in space divided by the magnitude of the test charge. In other words, it indicates the force per unit positive charge at that point in time.

The existence of electric charges in the surrounding space affects the intensity of the electric field. Electric charges produce an electric field, and the strength of this field's impact on other nearby charges is measured by the electric field intensity. The direction of the electric field intensity can be determined by the direction of the force exerted by a positive test charge, whereas the magnitude is determined by the force-to-test charge magnitude ratio.

Electric field intensity

Image: Electric field intensity

Even when the test charge is at rest, it will still experience force since it is exposed to the source charge's electric field. The electric field intensity has no effect by the mass and velocity of the test charge particle. It only relies on the amount of charge on the test charge particle. The test charge may be a positively or negatively charged particle.

Electric field intensity can be given as

Where

E = electric field intensity

F = force

Q = charge

Properties of Electric Field

The electric field has certain properties such as the following:

Electric fields are vector quantities, meaning they have both magnitude and direction. An electric field's direction at any given point is the direction in which a positive test charge could move if it were placed at that point.
The overall electric field at a point generated by a multitude of charges is the vector sum of the individual electric fields generated by each charge.
The intensity of an electric field reduces with the square of its distance from the source charge, according to the inverse square law that governs electric fields.
Electric fields have the ability to exert forces on other charges when they come into contact with them.
Electric fields are constantly perpendicular to equipotential surfaces, that is, imaginary surfaces connecting points with the same electric potential.

Electric Field Intensity Due to a Point Charge

Coulomb's law outlines the force that exists between two point charges and serves as a foundation for understanding the electric field. Since the electric field intensity is inversely square-related to distance from the point charge, it decreases quickly as distance increases.

When there is a positive point charge, the intensity of the electric field is directed radially away from the charge, and when there is a negative point charge, the direction is radially inward towards the charge.

The formula for electric field intensity due to a point charge is given by