A point charge Q is placed at the corner of a square of side a. Find the flux through the square.

Explanation

A corner of a cube can be supposed to be the centre of a big cube made up of 8 such cubes, therefore flux through it is `q//8 epsilon_(0)`. The directon of E is parallel to the three faces that pass through this face, thus flux through these is zero.

Flux through the other three faces
`=1/3 (q/(8 epsilon_(0)))=q/(24 epsilon_(0))`