- #1

Iftekhar Uddin

- 7

- 0

1. Homework Statement

1. Homework Statement

*A uniformly charged, straight filament 7.70 m in length has a total positive charge of 2.00 µC. An uncharged cardboard cylinder 1.50 cm in length and 10.0 cm in radius surrounds the filament at its center, with the filament as the axis of the cylinder.*

(a) Using reasonable approximations, find the electric field at the surface of the cylinder.

(b) Using reasonable approximations, find the total electric flux through the cylinder.

(a) Using reasonable approximations, find the electric field at the surface of the cylinder.

(b) Using reasonable approximations, find the total electric flux through the cylinder.

## Homework Equations

The Electric Field of a filament is λ/2πRε

λ=Total charge/length

## The Attempt at a Solution

(I got the solution but I have questions about part A)[/B]

* I found that the answer to A was the electric field of a filament with r = .1m. I used this equation on an earlier problem that asked for the electric field at x distance away from the filament. But this is the same for this cardboard cylinder? I don't have to multiply it by the length of the cylinder? Why? The only reason I could think for this is that I'm finding a uniform E so I'm just finding E at a distance of R radially. Is that correct?

* Is cardboard not an insulator? If so, it doesn't affect the electric field at all? I thought that as an insulator it'd affect the electric field so that the outside surface of the insulator would have an E of 0.