Potential difference of a ring rolling in magnetic field

[berkeman]

Thread closed for Moderation...

 

[berkeman]

A couple posts were removed by the request of the poster (along with a reply to the posts), and the thread is re-opened for now. Thanks everybody for your patience.

 

[rude man]

I deleted my posts (##25 ff.) since my argument was not really relevant. @ergospherical 's explanation is certainly correct but his statement "The assumption of a constant and uniform magnetic field means there is a well defined electric potential field" is IMO not obvious to an introductory physics student. Interestingly, his E field is the irrotational field formed by charge buildup while $\bf v \times \bf B$ is the induced, and therefore non-conservative component.

Note too that if the observer were to move with the ring then the latter term would be absent, implying in its place a second E field to null the irrotational one. The physics in either case is obviously the same. If this is not accepted then we need to throw out the well-worn dictum that "the net E field in a conductor is zero".

 

[berkeman]

Thread closed again for Moderation...

 

[berkeman]

Sigh, after multiple thread derailments, this thread will remain closed.