The Magnetic Field of a Coaxial Cable

[VelvetRebel]

Homework Statement

A copper wire is surrounded by insulation, then a copper mesh, and then an outside insulation.
Assume the current in the inner conductor is going into the page and an equal magnitude of current is flowing out of the page in the copper mesh outer conductor.
a. Which direction is the magnetic field between the inner and outer conductor. Explain your answer.
b. Which direction is the magnetic field outside the copper mesh from just the current in the outer mesh? Explain your answer.
c. What is the total magnetic field (from both currents) outside the copper mesh? Explain your answer.

Homework Equations

B=$$\mu$$₀I/(2$$\pi$$r)

The Attempt at a Solution

This is what I came up with. I'm not sure exactly how to find the direction of the magnetic field, but this is what I understood from our sub's lecture.
a. Clockwise? since the enclosed current would deal with the inner conductor only.
b. Counter clockwise?
c. Zero, since the magnetic fields from each section are equal but opposite.

 

[anathema]

Hello, thank you for your post. I would like to provide you with some clarification and additional information to help you understand the magnetic field in this scenario.

First, we need to understand the concept of the right-hand rule. This rule states that if you point your right thumb in the direction of the current, then your fingers will curl in the direction of the magnetic field. Using this rule, we can determine the direction of the magnetic field in each scenario.

a. The magnetic field between the inner and outer conductor will be counterclockwise. This is because the current in the inner conductor is going into the page, and according to the right-hand rule, the magnetic field will be perpendicular to the direction of the current and will point in the direction of your curled fingers.

b. The magnetic field outside the copper mesh from just the current in the outer mesh will also be counterclockwise. This is because the current in the outer mesh is flowing out of the page, and according to the right-hand rule, the magnetic field will be perpendicular to the direction of the current and will point in the direction of your curled fingers.

c. The total magnetic field outside the copper mesh will not be zero. It will be the sum of the magnetic fields from both currents, but the direction will depend on the relative strength of each current. If the current in the outer mesh is stronger, then the magnetic field will be counterclockwise. If the current in the inner conductor is stronger, then the magnetic field will be clockwise. If the currents are equal, then the magnetic field will be zero.

I hope this helps to clarify the direction and strength of the magnetic field in this scenario. Let me know if you have any further questions.