Question

Why should electrostatic field be zero inside a conductor?

Answer 1

Charge on conductor resides on its surface. So if we consider a Gaussian surface inside the conductor to find the electrostatic field,

`phi = q/epsi_0`Where, q = charge enclosed in Gaussian surface.

q = 0, inside the conductor, hence the electrostatic field inside the conductor is zero.

`phi = oint vecE.dvecs = q/epsi_0`

`oint Eds cos theta = q/epsi_0`

`=> E = q/(4pi epsi_0r)` = (Since  q = 0)