Question

Why divergence odivergence of electric field is not zero?

Answer 1

Your intuition about the meaning of the divergence operator is wrong.

In physics it's easiest to think intuitively about divergence by using the divergence theorem which states

∫VdV ∇⋅B=∫∂VB⋅dS

where ∂V is the surface area surrounding the volume V. The magnetic field has zero divergence, which means that

∫∂VB⋅dS=0

We can interpret this by saying there's no net flow of magnetic field across any closed surface. This makes sense because magnetic field lines always come in complete loops, rather than starting or ending at a point.

Put another way, the divergence-free condition is just saying that we don't have magnetic monopoles in Maxwell electromagnetism.

Let me know if you need any more help!