# A charge Q is placed at a distance $\;\large\frac{a}{2}\;$ 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

$(a)\;\large\frac{Q}{\in_{0}}\qquad(b)\;\large\frac{Q}{3 \in_{0}}\qquad(c)\;\large\frac{Q}{6 \in_{0}}\qquad(d)\;\large\frac{Q}{2 \in_{0}}$

Answer : (c) $\;\large\frac{Q}{ 6 \in_{0}}$
Explanation :
Imagine a cube of edge a , enclosing the charge . The square surface is one of the six faces of this cube . According to Gauss's theorem in electrostatics , total electric flux through the cube = $\;\large\frac{Q}{\in_{o}}$
Flux through the square surface = $\; \large\frac{Q}{6\in_{0}}$

edited Aug 13, 2014