A charge q is placed at O in the cavity in a spherical uncharged conductor, Point S is outside the conductor. If q is displaced from O towards S (stilI remaining within the cavity)
By Gauss's law , the electric field at S is E.4πr2=qenϵ0⇒E=qen4πϵ0r2 where r= distance from center to S.
When we move charge q towards S within cavity, the enclosed charge qen will remain same i.e, qeq=q.
Thus, the field at S will not change.