Suppose that a spherical shell $B$ has inner radius $a$ and outer radius $b$ with a spherically symmetric internal charge density $\rho®=10kr^2$. What is the total charge?
Suppose instead that the shell is cylindrical, with the same inner and outer radii, but with a cylindrically symmetric internal charge density $\rho®=10kr^2$. What is the total charge?
Do you see the difference?? The coordinates $r$ in these two examples are different, with the first being the spherical radius, and the second being the cylindrical radius!
: Add some questions about theta and delta functions and limits