I have a question about a velocity selector. If one shoots a positive particle like a H+ cation through the selector, how can one force the particle to go more toward either the positive or negative plate? In general, one wants for the magnetic and electric fields to be equal and opposite and thus the particle can move straight. However one can alter either the magnetic or electric fields to force the particle toward a particular pole, correct? Once can also increase the velocity of the particle. If the velocity is increased, then B would decrease and so the particle's direction would be dictated by the Electric Field, correct?

The deflection is dictated by both E and B, and the B is velocity-dependent. You can choose a variety of paths, depending on the values of the fields.

Cool. Thanks a lot for the clarification. Is it possible to alter either the electric or magnetic field or does one only alter one of them? Also if one increase either the magnetic or electric field does the other field increase as well of you would need to increase it manually in order for the two to balance out?

Cool. Thanks a lot for the clarification. Is it possible to alter either the electric or magnetic field or does one only alter one of them? Also if one increase either the magnetic or electric field does the other field increase as well of you would need to increase it manually in order for the two to balance out?

 

If you alter one but not the other, you will select a different velocity. The velocity depends on the ratio of the fields. qE = qvB, so v = E/B for no deflection.