# Magnetization of atom

1. Dec 26, 2016

### Lord33

1. The problem statement, all variables and given/known data
We have coaxial cabel with radius R and R0=3R filled with magnetic.Magnetization J(r)=(r3-R3)/(2R3)*I/(2*pi*r).What is the magnitization if r=0(center of atom)?And what a magnetization direction of atom?

2. Relevant equations

3. The attempt at a solution
I think what magnitization in center of atom = -inf , but it is wrong.

2. Dec 26, 2016

### Staff: Mentor

The formula for the magnetization works in a limited range (for r) only. Can you find that range?
You can modify the formula a bit to make it applicable at r=0.

3. Dec 26, 2016

### Lord33

I understand what we must take radius of atom but how i can modified a formula if r<ra?I find limit and get -inf it is wrong.I know that J=∑P/ΔV.

4. Dec 27, 2016

### Staff: Mentor

You don't need the radius of an atom.

Your formula has an I in it. What is that? A current, sure, but a current of what? Every cable in the universe? Which current exactly do you have to consider in that formula, and is it the same current for every place?