What should be the angle of a field line with the normal to a surface so that flux linked with the surface becomes maximum?

Explanation

Let the intensity of the electric field E make an angle `theta` with the normal to a surface element ds .
Flux linked with the surface `=Ecos theta dS`
Now, `E cos theta dS` will be maximum if `cos theta=1, i.e., theta =0^(@)`.
So, if the field line make an angle `0^(@)` with the normal to the surface, the flux linked with the surface becomes maximum.