Calculating Alternating Voltage of Conductor in Magnetic Field

AI Thread Summary
To calculate the alternating voltage of a conductor loop in a magnetic field, the user seeks to apply the equations U=\oint (v×B) ds and U=\int rot(v×B) dA, but is unsure how to handle the rotation term. The discussion emphasizes that the electromotive force (emf) generated in the loop is determined by the coil's movement through the magnetic field at any moment. It suggests calculating the emf at various points during the rotation by considering the tangential velocity and the angle of the coil. The concept of visualizing the magnet rotating around the wire instead of the wire moving through the magnetic field is also proposed as a helpful perspective. Understanding these principles is crucial for deriving the equation for alternating voltage effectively.
Gavroy
Messages
232
Reaction score
0
Hey,
I asked myself, how can I use:
U=\oint (v\times B) ds(1)
to calculate for example the alternating voltage of a conductor loop turning in a constant magnetic field. But I am not only interested in this case, I just want to illustrate it.
Therefore I thought about using Stokes theorem:
U=\int rot(v\times B) dA(2)
But I do not know how to deal with rot(v\times B) in this equation.
How could I for exmple derive the equation of the alternating voltage
by using either equation 1 or 2.

Sorry about my english, but I do not live in an english-speaking country;-)
 
Physics news on Phys.org
The emf produced in the loop at any given moment is simply that produced by the movement of the coil through whatever field it is experiencing at that time.

So all you need to do is to work out the emf produced at each point in the rotation by the tangential velocity through the field at whatever angle it is currently at. (Think about it in terms of rotating the magnet around the wire instead of vice-versa).
 
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