Question 2 (4pts) A thick spherical shell, with inner radius a and outer radius b, is made of dielectric material with a "frozen-in" polarization P(r) = where k is a constant and r is the distance from the centre, as shown. Find the electric field in all three regions by two different methods: a) Locate all the bound charge, and use Gauss's law to calculate the field it produces. E-dã = Qene €0 b) Use Gauss's law for the electric displacement D to find D, then get E from ĎE + P. fĎ · dã = Qfenc P P