http://img404.imageshack.us/img404/4148/gauss3j.png (infinitly long)

[latex]\Phi=\Phi_{0}(1-{r \over R}) {C \over m^2}[/latex]

What's the charge of the cylinder of length L?


I have done some calculations, but they were all wrong (checked by teacher).

 

1. What problem are you try to solve (and what are your assumptions? e.g. charge density)? What do your symbols denote (e.g. what are C and m)?
2. What did you do in your attempt to solve it? (and why, if it's not obvious)

 

Are you attempting to find the electric field at a given distance due to a uniform line charge of an infinite length whose charge per unit length is given? ...

 

C over m are units. It should be m^3 actually.

Anyway, question I gave you is additional one. The more important one is what is the electric field when r<R?

 

C over m are units. It should be m^3 actually.

Anyway, question I gave you is additional one. The more important one is what is the electric field when r<R?

 

C over m are units. It should be m^3 actually.

Anyway, question I gave you is additional one. The more important one is what is the electric field when r<R?

When r is less than R the electric field is zero.

 

I am fighting with this: http://img202.imageshack.us/img202/5889/physics.jpg

How should I do this properly?

 

You can assume an area inside the cylinder and calculate the net electric flux throught it.

 

The electric field within an infinitely long cylinder with a uniformly charge density can be calculated as per the following link:

http://ecee.colorado.edu/~bart/book/book/chapter1/pdf/ex1_4.pdf