# What happens when there is a cavity inside a conductor and a  charge q is placed in it?

Aman Bansal
592 Points
12 years ago

Dear Swapan,

consider a gaussian surface infinitesimally outside the cavity surface. because it lies in a conductor, electric field is zero throughout the surface. thus, from Gauss law charge enclosed by the surface is zero which implies that a total charge -q is induced on the surface of the cavity.now, the conductor carries zero net electric charge. Consider a gaussian surface infinitesimally inside the conductor. because it isa condutor, field is zero throughout the surface and from gauss law,charge also is zero(cavity surface charge: cavity surface induced charge -q+charge inside cavity(+q)). However, the conductor is electrically neutral and  conductor has zero net charge. -q is induced on surface of cavity.Therefore the +q of the conductor is distributed over the outer surface of the conductor

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Thanks

Aman Bansal