- #1
jegues
- 1,097
- 3
Homework Statement
See figure attached.
Homework Equations
The Attempt at a Solution
I'm confused as to how they got their D(r)
Using Gauss' Law,
For r < or = a
[tex]\oint_{S} \vec{D} \cdot \hat{n} dS = \int_{v} \rho dv [/tex]
[tex]D(4 \pi r^{2}) = \frac{\rho 4 \pi r^{3}}{3}[/tex]
[tex]\Rightarrow D = \frac{P_{0}r^{2}}{3a}[/tex]
What am I doing wrong?