A square surface of side `L m` is in the plane of the paper. A uniform electric field `vec(E )(V//m)`, also in the plane of the paper, is limited only to the lower half of the square surface (see figure). The electric flux in `SI` units associated with the surface is:

Explanation

A electric flux` phi_(E)=intE.ds`
` =intE ds costheta =intEdscos90^(@)=0`
Thus the lines are parallel to the surface.