question_answer

    A point charge + q is placed at the midpoint of a cube of side L. The electric flux emerging from the cube is

A)  \[\frac{q}{{{\varepsilon }_{0}}}\]                                             

B)  \[\frac{q}{6{{L}^{2}}{{\varepsilon }_{0}}}\]

C)  \[\frac{6q{{L}^{2}}}{{{\varepsilon }_{0}}}\]                         

D)  zero

Correct Answer: A

Solution :

                From Gauss theorem, the electric flux\[(\phi )\]through any closed surface is equal to\[\frac{1}{{{\varepsilon }_{0}}}\]times the net charge q enclosed by the surface. Thus,                 \[\phi =\int{\overrightarrow{E}}.dA=\frac{q}{{{\varepsilon }_{0}}}\]