Motion of a charge in magnetic field Let us assume, we have a charge (let's say an electron) at rest in a uniform magnetic field (assume magnetic field is along z-direction).  Suddenly magnetic field is switched off in a very short span (assume almost instantaneous).  What will happen to the charge? will it move? if yes, what will be the path traversed by the charge particle?
My thought: I believe when magnetic field is switched off in very short span, the change in magnetic field induces an electric field (from Maxwell's equations), so there will be motion, but I don't know which direction and what path will the charged particle move? can someone help or atleast give hint
 A: There won't be any emf and  there won't be any movement.
It could be concluded from symmetry considerations.
You can also check out the non-wire case on this site https://en.m.wikipedia.org/wiki/Faraday%27s_law_of_induction.
A: The magnetic field cannot be uniform throughout all space. It can be uniform in limited space but will become more and more non-uniform outside its boundary.$^*$ This boundary is due to distribution of charges and currents in the space that maintain that magnetic field. Also the exact shape of the induced electric field will depend on this distribution. In other words, the question is not answerable because the situation is not fully specified.
$^*$ Uniform magnetic field free of boundaries is a mathematically valid state of the field which is consistent with Maxwell's equations, but it is an unphysical situation in the sense there is no physical arrangement of matter that produces such a field.
We can answer the question for a specific realistic case of uniform field, such as magnetic field inside a long tube that is carrying electric current on its surface. There the induced electric field will be concentric with the tube walls and its maximum value will be attained near the inner surface of the tube.
