An unknown charged particle is fired into a velocity selector with controllable electric and magnetic fields.  The animation shows a top view of the apparatus. The magnetic field points into or out of the view depending on the sign and the electric field is up or down depending on the sign.  Enter E and B field values

Ey= Bz=

and press the play button every time you wish to change the field. Observe the force vector on the particle.  The value of Ey is constrained to -10 < Ey < 10 and the value of Bz is constrained to -5 < Bz < 5.   Start