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Electric Flux - Practice Questions & MCQ

Edited By admin | Updated on Sep 18, 2023 18:34 AM | #JEE Main

Quick Facts

  • Electric flux(I) is considered one the most difficult concept.

  • 21 Questions around this concept.

Solve by difficulty

A cone of base radius R and height $h$ is located in a uniform electric field $E$ parallel to its base. The electric flux entering the cone is :

Shown below is a distribution of charges. The flux of the electric field due to these charges through the surface S is

Concepts Covered - 1

Electric flux(I)

Electric flux-

To understand the concept of electric flux let us take an example - 

Let us consider an electric field that is uniform in both magnitude and direction. Let these field lines penetrate a rectangular surface of area A whose plane is oriented perpendicular to the field lines. As the number of of lines per unit area is proportional to the magnitude of electric field. So the total number of lines penetrating is proportional to E.A. The magnitude of this product is known as Electric flux, which is denoted by - 

                                                                           

$
\phi_E=E A
$


So,
Electric flux ${ }^\phi$ ): Electric flux through an area is the number of electric field lines passing normally through the area.

                                    

Flux through an area dA is given by

$
d \phi=\vec{E} \cdot \vec{d} A=E d A \cos \theta
$

here, $\theta$ is the angle between the area vector and the electric field.
- Total flux through area $A$ is

$
\phi=\int \vec{E} \cdot \vec{d} A
$

- Flux is a scalar quantity so they can be added algebracally.
- The Sl unit of flux is volt-meter

 

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Electric flux(I)

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