Deep inside a block of electret whose polarisation is frozen in

PHYSICS · Subjective · Fermi University Physics · Electricity, Magnetism & Electromagnetism · Electric fields in matter · Electric fields in matter

The Boundary-Value Problem, Ch Polarisation and bound charge, completed

Problem

Deep inside a block of electret whose polarisation is frozen in, the macroscopic field is

E = 1.0\times10^{4}\,\mathrm{V\,m^{-1}}

and the polarisation, parallel to

\mathbf{E}

, is

P = 1.0\times10^{-7}\,\mathrm{C\,m^{-2}}

. A small spherical cavity is cut in the block, far from any edge of the block. Find the electric field at the centre of the cavity.