Conductors And Dielectrics

Inside a conductor in electrostatic equilibrium the free electrons redistribute themselves until they cancel any internal field, making the net electric field zero throughout the material, a key result in NCERT Class 12, Chapter 1 (Electric Charges and Fields). If any field remained, the mobile charges would continue to move, contradicting the equilibrium assumption; motion stops precisely when the interior field is zero. Consequently all excess charge resides on the outer surface. The option of a reversed surface field is wrong because although the field is zero inside, it is nonzero just outside and perpendicular to the surface, not merely reversed. The option of a maximum field at the centre is wrong because there is no field anywhere inside, let alone a maximum. The option of a uniform outward field inside is wrong because that would drive charges perpetually and violate equilibrium. This property is the basis of electrostatic shielding, which is why sensitive electronics are enclosed in metal boxes to keep external fields out. A consistency check via Gauss's law confirms the result: a Gaussian surface drawn wholly inside the conductor encloses no net charge, so the flux through it and hence the interior field must both be zero.