If i have a wire that has current flowing some direction and i enter it into an magnetic field, how do i know that it reverses direction? It has something to do with faraday..but i don't completely understand

Question

egenriether · Answer

are you asking how you'd know if the current changed direction in a wire that is in a magnetic field?

anonymous · Answer

yes, i think ..

egenriether · Answer

a current-carrying wire has its own magnetic field, due to Ampere's Law.  The direction of the field (clockwise or counter-clockwise) around the wire depends on which way the current is traveling.  If a wire in an external magnetic field had its current change directions it would experience a change in the forces acting on it.

anonymous · Answer

So, if i had a current flowing the opposite way the force was (before it entered the field) it would induce and switch direction? kinda?

anonymous · Answer

Magnetic force on a moving charge is perpendicular to the velocity of the charge so I wouldn't expect to see reversal of current in a uniform magnetic field. The electrons will flow in the usual direction in the wire but will be pushed sideways by the magnetic force. http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/forwir2.html --- If you don't mind an off-topic link I found while searching online... I found a video of motion of a free charged particle in uniform electric field and magnetic field that are perpendicular to each other. The overall direction of motion is not what I expected. http://www.windows2universe.org/earth/Magnetosphere/tour/tour_earth_magnetosphere_06.html I would have expected it to drift along the direction of electric field. This is counter-intuitive for me, but I guess it works out this way.