13 Electric Flux Examples : Detailed Explanations

This article discusses about electric flux examples. Flux is a group of particles that enters or leaves a surface or system. In this article we shall study about electric flux.

Electricity is the flow of electrons through a system. The system has to be a good conductor of electricity. Conductor of electricity simply means that it has to be able to conduct the flow of electrons through it. In this article we shall study about electric flux and and related examples.

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Example 14

What is electric flux?

Electric flux is the number of electric field lines or electric lines of force that pass through a given area. The lines of electric field originate from positive terminal and exit at negative terminal.

The simple sign convention states that the field lines going inside a closed surface are considered as negative and similarly the field lines originating from a surface are considered as positive. The field lines are vector quantity because they have magnitude and direction both.

electric flux examples — **Image: Solenoid**

Image credits: Geek3, VFPt Solenoid correct2, CC BY-SA 3.0

What is Gauss law?

Gauss law exists for both electricity and magnetism We shall study about Gauss law for electric field. Gauss law gives a relation between electric flux and electric charge.

Gauss law for electric field states that electric field across a surface of closed system is directly proportional to the net electric charge enclosed by the surface. This law explains the fact that like charges repel and unlike charges repel. We shall study more about electric flux in later sections of this article.

Laws of electromagnetism

Electromagnetism gives a direct relationship between electricity and magnetism. It combines the effect of both electric field and magnetic field. Let us study the laws of electromagnetism.

The laws of electromagnetism are given in the section below-

Faraday’s laws of induction– Most electric motors make use of this law. This law states that a voltage or emf is induced inside the coil when the magnetic field around it changes in magnitude or direction.
Lenz’s law– This law is analogous to Newton’s third law of motion. This law states that when emf is generated inside a coil due to change in external magnetic field, it generates a current whose magnetic field is in the opposite direction to the original magnetic field that produced the emf.
Lorentz force– Lorentz force is the force that a particle experiences due to change in electric and magnetic field changes.
Amperes circuital law– The line integral of magnetic field that surrounds the closed loop is equal to the algebraic sum of currents passing through the loop.

Electric flux examples

Below is a list of examples of electric flux with their solutions. The numericals are very easy to understand, let us have a look.

Example 1

Calculate the electric flux striking on a plane of 1 m2 on which an electric field of 2 V/m passes through an angle of 30 degrees.

Solution: The formula for electric flux is-

π = EA Cos θ

Substituting the values in the formula we get, electric flux = 1Vm

Example 2

Calculate the electric flux striking on a plane of 1m2 on which an electric field of 0.04V/cm passes through an angle of 30 degrees.

Solution:

First we change 0.04V/cm to SI units. It becomes 4V/m.