A charge Q is placed at a distance `alpha/2` above the centre of a horizontal, square surface of edge a as shown in figure (30-E1). Find the flux of the electric field through the square surface.

Options

A. `Q/(6epsilon_0)`
B. `Q/(2epsilon_0)`
C. `Q/(3epsilon_0)`
D. `q/epsilon_0`

Answer

A

Explanation

We can use five more square plates of same dimensions to complete the cube in such a manner that charge is at the centre of cube. Using Gauss theorem we can understand that total flux associated with complete cube is `Q/epsilon_0`. Charge is at the centre hence flux is symmetrically distributed anmong all six surfaces of cube. So flux associated with given single square plate must be 1/6 of total flux. Hence flux associated with given square plate is `Q/(6epsilon_0)`.