Velocity selector A Level & charge to mass ratio for an electron

A Level magnetism - especially suited for CIE Cambridge international A Level. Explains:
How a velocity selector works
Why it is useful
How this is used to find the mass to charge ratio of an electron.

[@darshan5044]

I'm pretty late. But fantastic video! I liked that you mentioned it not being exactly vacuum because most sources leave it out for the reader/viewer to find themselves out (which is not exactly good service). Wish to see more from you. Good wishes.