Griffiths Problem 4.10: Finding Sigma for Polarization Vectors

[m0nk3y]

Homework Statement

I have a problem exactly like problem 4.10 in griffiths, however that problem is not being much help since it seems to me that they just plug in P(r).

For those who do not have griffiths the question is:
A sphere of radius R carries a polarization P(r)=kr
where k is a constant and r is the vector from the center

Homework Equations

$$\sigma$$=P*nhat

The Attempt at a Solution

answer is sigma=kR

Thanks

 

[Mindscrape]

What do you mean? You need to use the definitions of bound surface and volume charges, which are dependent on P. If by plug in you mean they plug it into the equations, then yes, you just use the definitions.

 

[Biest]

You are right, but that question asks for more