I believe there is another case, very similar (also involving a closed loop): If you pass a (properly oriented) magnet through or even across the opening of suc

I believe there is another case, very similar (also involving a closed loop): If you pass a (properly oriented) magnet through or even across the opening of such a loop, an electrical current will flow around the loop (while the rest of the atomic bits will stay more or less in the same place ;) ) and no charge will accumulate. (This caught my attention because I had up to that point believed that electrical fields are always conservative, and this demonstrates that not to be true: an electron traveling around the loop in such a manner will eventually return to its starting point having done non-zero work)