Electric Flux Formula

Electric Flux Formula

When it comes to studying physics and how electricity works, there is an endless amount of knowledge and information to be gained. The idea of electric flux is one such scientific investigation. It is relevant to our knowledge of electric force and its behaviour. Let’s learn more about the concept of electric flux.

Electric Flux

Electric flux is a characteristic of an electric field. It may be thought of as the number of forces that intersect in a specific location. Electric field lines are typically thought to begin on positive electric charges and conclude on negative charges. Field lines going into a closed surface are considered negative, whereas those directed out of a closed surface are positive.

If there is no net charge within a closed surface, every field line put into it travels into the interior and is often directed outward somewhere on the surface. The negative flux is equal in size to the positive flux, resulting in a net or total electric flux is equal to zero.

If a net charge is confined within a closed surface, the total flux through the surface is proportional to the enclosed charge, which is positive if positive and negative otherwise.

Formula for Electric Flux

The mathematical relationship between electric flux and the contained charge is known as Gauss’ law of the electric field. This is one of the fundamental rules of electromagnetic. In the related meter-kilogram-second system and the International System of Units (SI), the net flux of an electric field through any closed surface is typically equal to the contained charge in coulombs divided by a constant known as the permittivity of free space.

In the centimeter-gram-second system, the net flow of an electric field through any closed surface is compatible with 4π times the contained charge, measured in electrostatic units (esu). Electric flux is proportional to the number of electric field lines that pass through a virtual surface. This may be understood using an equation. The electric flux is the total number of electric field lines moving across a specific region in a unit period.

Thus, In the same way that the plane is normal to the flow of the electric field in the preceding example, the total flux is given as:

The Electric Flux Formula  = EA cos θ


  • E is the magnitude of the electric field
  • A is the area of the surface through which the electric flux is to be calculated
  • θ is the angle made by the plane and the axis parallel to the direction of flow of the electric field

Solved Examples

Question: An electric field of 800 V/m makes an angle of 30.00 with the surface vector. It has a magnitude of 0.800 m2. Find the electric flux that passes through the surface.

Solution: The electric flux which is passing through the surface is given by the equation as:

ΦE = E.A = EA cos θ

ΦE = (800 V/m) (0.800 m2) cos 30

ΦE = 320 V m

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Electric Field Formula Poynting Vector Formula
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Capacitance Formula Uniform Circular Motion Formula
Centripetal Force Formula Thermal Expansion Formula
Distance Speed Time Formula Thermal Energy Formula
Ohms Law Formula Amperes Law Formula
Refractive Index Formula Horsepower Formula
Wavelength Formula Lattice Energy Formula
Stress Formula Length Contraction Formula

FAQs (Frequently Asked Questions)

1. What is an electric field?

An electric field is the physical field that surrounds electrically active particles or substances. It acts on every other charged particle or body in the field, either repelling or attracting them. In other terms, it is the physical field around a body of charged particles.

2. What is an electric flux?

The electric flux is the total number of electric field lines that travel through a specific region in a unit of time.

3. What is the unit of electric flux?

The SI base unit of electric flux is voltmeters (V m).