Question

A charge $$Q$$ is placed at a distance $$\dfrac{a}{2}$$ above the centre of a horizontal, square surface of edge a as shown in figure. Find the flux of the electric field through the square surface.

Answer 1

Given

A charge is placed $$O$$ a plain surface with area $$=a^2$$,

about $$\dfrac{a}{2}$$ from its centre.

Assumption : let us assume that the given plain forms a surface of an imaginary cube.

Then the charge is found to be at the centre of the cube.

Hence flux through the surface $$= \dfrac{Q}{\varepsilon_0} \times \dfrac{1}{6} = \dfrac{Q}{6\varepsilon_0}$$