Current Inside long cylindrical Conductor

AI Thread Summary
The discussion centers on understanding Ampere's law in relation to a long cylindrical conductor with a uniform current distribution. A user initially seeks clarification on how to calculate the current through an Ampere's surface outside the cylinder, specifically questioning the formula (r^2/R^2)*I. After some contemplation, the user realizes they misread the material and resolves their confusion. The interaction highlights the learning process involved in grasping concepts of electromagnetism. Overall, the thread illustrates the challenges beginners face when studying complex physics topics.
Tom McCurdy
Messages
1,017
Reaction score
1
Hi guys,

I was wondering if someone could help explain something to me. I am just starting out learning about Ampere's law. I am looking at this example in the book and I don't get it. They have a cylindrical conductor with Radius R and current I. The current is uniformly distributed over the cross sectioanl area of the conductor. They take a surface that is like an extended circle outside the cylinder which makes sense to me, but I don't get how the current would be
(r^2/R^2)*I
where r is the radius of the circle of the ampere surface outside the cylinder.:confused:
 
Physics news on Phys.org
Haha Nevermind I figured it out... I misread something sorry for posting
 
Thread 'Motional EMF in Faraday disc, co-rotating magnet axial mean flux'
So here is the motional EMF formula. Now I understand the standard Faraday paradox that an axis symmetric field source (like a speaker motor ring magnet) has a magnetic field that is frame invariant under rotation around axis of symmetry. The field is static whether you rotate the magnet or not. So far so good. What puzzles me is this , there is a term average magnetic flux or "azimuthal mean" , this term describes the average magnetic field through the area swept by the rotating Faraday...
Back
Top