Electric Flux MCQ - Practice Questions with Answers

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

Flux through an area $d A$ 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 SI unit of flux is volt-meter