A beam of electrons passes underfected throgh unifromly perpendicular electric and magnetic fields. If the electric field is swiched off, and the same magnetic field is maintained the electrons move:

Options

A. along a straight line
B. in an elliptical orbit
C. in a circular orbit
D. along a parabolic path

Answer

C

Explanation

`e^-` will moves undeflected in a crossed `vecE` and `vecB` whre `vec v bot vecE bot vecB` . If `vecE` is switched of `vecc bot vecB` so `e^-` will make circular motion