1. Oct 30, 2012

### Josephk1508

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

Show that, if a charge distribution  has cylindrical symmetry, then knowing the value
of Qzz allows you to determine the entire quadrupole moment matrix.

2. Relevant equations

Tr Q=0, ie Qxx+Qyy+Qzz=0

3. The attempt at a solution

Because of the cylindrical symmetry, the charge density changes as a function of ρ, where ρ=(x^2+y^2)^1/2. Then I don't really know where to go from there.

2. Oct 30, 2012

### Josephk1508

I have now worked out all values for the quadrupole matrix, I just need to calculate what Qzz is. If anyone can help that would be really useful. Also I realised I made a mistake above, cylinrical symmetry means that it is dependent only z only.