Electric Field in and outside a cylinder

In summary, the formula for an infinitely long cylinder with charge density lamda and radius R is E = (lamda) / (2 pi epsilon not * r). When r < R, E is undefined, and when r > R, E = (lamda * r) / (2 pi epsilon not * R^2). Gauss' law can be applied to solve this problem, where the flux is equal to the integral of E dotted with dA, which can be simplified to EA due to the symmetry of the problem. The area would be equivalent to pi r squared times the length, and the charge enclosed would be lamda times the length.
  • #1
reising1
54
0
An infinitely long cylinder has charge density lamda and has a radius R.

What is E when r < R and when r > R.

I know the formula for an infinite line of charge is
E = (lamda) / (2 pi epsilon not * r)

Thanks!
 
Physics news on Phys.org
  • #2
reising1 said:
An infinitely long cylinder has charge density lamda and has a radius R.

What is E when r < R and when r > R.

I know the formula for an infinite line of charge is
E = (lamda) / (2 pi epsilon not * r)

Thanks!

do you know Gauss' law?
 
  • #3
Yes. Flux = q enclosed / Epislon
 
  • #4
reising1 said:
Yes. Flux = q enclosed / Epislon

Hah. Well, have you tried to apply Gauss' law to this problem? The forum rules forbid posters from doing your homework for you. Instead, we are here to guide you. You won't get any help without posting the source of your confusion or posting work.

"here is the problem, thanks" is not acceptable
 
  • #5
Okay well I know that the integral of E dotted with dA is the flux, which can be simplifed to EA due to the symmetry of the problem. And the area would be equivlant to the pi r squared times length. And q enclosed would be lamda times L.
 

1. What is an electric field?

An electric field is a physical quantity that describes the force exerted on a charged particle by other charged particles in its surroundings.

2. How is an electric field created inside a cylinder?

An electric field is created inside a cylinder by placing a charged particle or a charged object inside the cylinder. The electric field is then created by the interaction of the charges on the particle or object with the charges on the walls of the cylinder.

3. How does the electric field inside a cylinder differ from the electric field outside?

The electric field inside a cylinder is constant and uniform, meaning it has the same magnitude and direction at all points. However, the electric field outside a cylinder varies depending on the distance from the cylinder and the charge on the cylinder.

4. Can the electric field inside a cylinder be affected by the material of the cylinder?

Yes, the material of the cylinder can affect the electric field inside it. If the cylinder is made of a conductive material, the charges on the walls of the cylinder will redistribute, resulting in a change in the electric field inside. If the cylinder is made of an insulating material, the electric field inside will remain constant.

5. How can the electric field inside a cylinder be calculated?

The electric field inside a cylinder can be calculated using the formula E = Q/2πεr, where Q is the charge on the cylinder, ε is the permittivity of the material, and r is the distance from the center of the cylinder.

Similar threads

  • Introductory Physics Homework Help
Replies
2
Views
973
  • Introductory Physics Homework Help
Replies
1
Views
1K
  • Introductory Physics Homework Help
2
Replies
64
Views
1K
  • Introductory Physics Homework Help
Replies
7
Views
2K
  • Introductory Physics Homework Help
Replies
2
Views
1K
  • Introductory Physics Homework Help
Replies
4
Views
1K
  • Introductory Physics Homework Help
Replies
11
Views
597
  • Introductory Physics Homework Help
Replies
4
Views
2K
  • Introductory Physics Homework Help
Replies
2
Views
984
  • Introductory Physics Homework Help
Replies
17
Views
285
Back
Top