An infinitely long, non-conducting cylinder of radius R carries a uniform volume charge density ρ. Find the magnitude of the electric field for 0 < r < R
The Attempt at a Solution
I am debating whether the answer should be ρr^2/2εoR or ρr/2εo.
I said E(2πRL)=(ρπr^2L)/εo and solved to get ρr^2/2εoR.
I was confident in my answer but then found the same problem in the book, but it asked to find E at distance r from axis, where r<R. The answer to this was ρr/2εo. Can someone explain the difference between these two problems, if there is one. They may be exactly the same and my calculation is wrong, but I am confused over the two