Magnetic Fields: I don't understand cylindrical current systems

In summary, the conversation discussed dealing with a system where a current is running inside a cylinder surrounded by a cylindrical shell. The main question was how to find the magnetic field in different areas of the system, including inside and outside the cylinder and in the shell. It was suggested to use Ampere's law for the inner current and to use a formula involving the permeability of space, current, and radii to find the magnetic field.
  • #1
Strawberry
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This is a really bad picture, but it should kind of give the idea.
How do I deal with a system where a current is running in a cylinder surrounded by a cylindrical shell? I know this sounds like a homework question, and it is related to a few of them, but it's the whole concept of the system I don't really understand. Basically I need to know how to find the magnetic field inside the cylinder, between the cylinder and the shell, in the shell, and outside the shell. Is it basically just a sum of the two independent fields? Also do the fields cancel outside of the shell if the currents are opposite?
 
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  • #2
So we are talking about a cylinder inside another one of a greater radius, like a piece of coaxial cable?
 
  • #3
If the cylinders are much longer than their radii, you can use Ampere's law for the inner current.
 
  • #4
Yes, What clem said is correct. using ampere law you can easyly find magnetic field inside and outside the cylinder. Assume your radius of the cylinder is R. then if you want to find the magnetic field outside the cylinder assume its outside radius(distance) is r then the formula is B(magnetic field)=(Permiabilityof the space*Current)/(2*pi*r). if you want to find the magnetic field inside the cylinder assume its inside radius(distance) is r then the formula is B(magnetic field)=(Permiabilityof the space*Current*r)/(2*pi*R*R).
 

1. What is a magnetic field?

A magnetic field is a region in space where a magnetic force is exerted on a magnetic object. It is created by the motion of electric charges, such as electrons, and can also be produced by magnets.

2. How do magnetic fields affect cylindrical current systems?

Magnetic fields can interact with cylindrical current systems, which are circuits that have a cylindrical shape and carry electric current. The magnetic field can cause the current to flow in a circular pattern around the cylinder, creating a magnetic field that is perpendicular to the direction of the current.

3. What is the difference between a magnetic field and an electric field?

A magnetic field is created by the motion of electric charges, while an electric field is created by stationary electric charges. Additionally, magnetic fields can only be detected by a magnetic object, while electric fields can be detected by both electrically charged and uncharged objects.

4. How is the strength of a magnetic field measured?

The strength of a magnetic field is measured in units of tesla (T) or gauss (G). One tesla is equivalent to 10,000 gauss.

5. Can magnetic fields be shielded?

Yes, magnetic fields can be shielded by using materials that are not affected by magnetic fields, such as iron or steel. This creates a barrier that redirects the magnetic field away from the shielded area.

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