A square surface of side $L$ metre in the plane of the paper is placed in a uniform electric field $E$…

A square surface of side $L$ metre in the plane of the paper is placed in a uniform electric field $E$ (volt/m) acting along the same place at an angle $\theta$ with the horizontal side of the square as shown in figure. The electric flux linked to the surface in unit of $V-m$, is
  1. $\mathrm{EL}^2$
  2. $\mathrm{EL}^2 \cos \theta$
  3. $\mathrm{EL}^2 \sin \theta$
  4. 0

Solution

Flux of electric field $\vec{E}$ through any area $A$ is defined as $\phi=\mathrm{E} \cdot \mathrm{A} \cos \theta$ or $\phi=\overrightarrow{\mathrm{E}} \cdot \overrightarrow{\mathrm{A}}=0$ the lines are parallel to the surface.

Asked in: NEET 2010 (Screening)

Practice more Electrostatics questions on Aicharya