Question

Electric field lines are always perpendicular to the surface of a charged body. Why?

Answer 1

It happens so as to minimise the energy dissipation.

Here, consider a situation wherein the field lines aren't perpendicular to the surface. Then according to basic vector knowledge we have two components of the electric field . One which is perpendicular to the surface and the other which is parallel, or here in this case coinciding with the surface.

So....when the numerical quantity of the components along the surface and perpendicular are computed taking angle theta as the angle between Electric field vector and the surface, the perpendicular component of vector comes out to be less than when the angle is 90° as then the parallel component would be E×Cos90°= 0.

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