A flat, square surface with sides of length L is described by the equations
`x = L, 0le y leL,0lezleL`
The electric flux through the square due to a positive point charge q located at the origin `(x = 0 , y = 0, z = 0)` is

Options

A. `q/(4epsilon_0)`
B. `q/(6epsilon_0)`
C. `q/(24epsilon_0)`
D. `q/(48epsilon_0)`

Answer

C

Explanation

c. Imagine a charge q at the center of a cube of edge length 2L
Then `phi = q//epsilon_0`. Here, the square is `1//24` of the surface area of the imaginary cube, so it intercepts `1//24` of the flux. That is ,
`Phi = q/(24epsilon_0)`