Surface polarization charge

miew

I have this problem for homework and I don't even know where to start... I would really appreciate any help !

1. The problem statement, all variables and given/known data

An isolated metal sphere of radius a has a free charge Q on its surface. The sphere is
covered with a dielectric layer with inner radius a, outer radius b, and dielectric
constant κ .
(a) Calculate the surface polarization
charge density pol σ on the inside
and outside surfaces of the
dielectric (linear dielectric).
(b) What is the volume charge density
pol ρ of polarization charge inside
the dielectric? Is this surprising?
Recall:
σ pol = rP •nˆ and ρpol = −∇ •rP .

2. Relevant equations

I don't even know where to start...



3. The attempt at a solution
1. The problem statement, all variables and given/known data



2. Relevant equations



3. The attempt at a solution