Question

A cube of side $l$ is placed in a uniform electric field $E\hat{i}$. Then the net flux through the cube is :

• A. $0$
• B. $l^{2}E$
• C. $4l^{2}E$
• D. $6l^{2}E$

Answer 1

The correct option is A $0$

Electric flux is given by $\text{electric field}\times \text{area vector}$

area vector is a vector drawn perpendicular to a given surface area directed outside and magnitude is equal to the area.

In a uniform field, the intensity of field on any two opposite sides will be equal.

But the area vector will be equal and opposite. Hence the total flux will be zero.