Question 284 of 311

Expression for an electric field is given by $\vec{E}=4000{x}^{2}\hat{i}V{m}^{-1}$. The electric flux through the cube of side $20cm$ when placed in electric field (as shown in the figure) is ______ $Vcm$.

Your answerCheck answer

Show answer and solution▾

Answer: 640

Electric flux is expressed as $\phi =\vec{E}\cdot \vec{A}=EA\cos \theta$, here, $A$ is area of the surface and $\theta$ is the angle between the electric field lines and the normal to $A$.
The flux will be only from DEFG surface as on the surface OABC field is zero and for rest of the surface, area vector is perpendicular to field.

So, $\phi =EA$
$=4000\times (0.2{)}^{2}\times (0.2{)}^{2}$
$=4000\times 16\times {10}^{-4}Vm$
$=640Vcm$