Electron Motion in a Magnetic Field: Kinetic Energy Considerations

[razvees]

Consider a region in which there is a magnetic field B, which is such that it has magnitude B and direction in the positive x-direction. An electron enters this region such that its velocity is in the positive y-direction. (a) Describe the motion of the electron in this region by considering the magnetic force on it. (Hint: as a third direction use into the paper or out of the paper). (b) What can you say about the kinetic energy of the electron?

 

[UbikPkd]

You have to use flemings left hand rule:

http://en.wikipedia.org/wiki/Fleming's_left_hand_rule

so your 1st finger (field) points in positive x direction (left to right on paper)

your second finger (current) points upwards towards the top of the paper

and your thumb (motion) points INTO the paper.

just be careful with this one, you can seriously sprain your fingers!