# Homework Help: Is the book wrong again for this e field problem?

1. Sep 6, 2011

### pyroknife

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

A nonconducting SPHERICAL SHELL of inner radius R1 and outer radius R2 has a uniform volume charge density p. Find the total charge on the shell

2. Relevant equations
Q=pV=p(4/3)*pi*(R2^3-R1^3) << That's what I got
the book had Q=pV=p(4/3)*pi*(r^3-R1^3) <<how can that be correct if you're finding the total charge the shell, not from R1 to r?

2. Sep 6, 2011

### Pi-Bond

Your answer is right, but are you sure that you are quoting the book correctly? The book could be referring to the charge contained within a radius r, such that R1<r<R2 (which can be applied to find the electric field by Gauss' law)