# Circluar beam

1. Apr 20, 2006

### teng125

how to prove that the circular beam consists of negative charged particles??

pls help

2. Apr 20, 2006

### Andrew Mason

AM

3. Apr 21, 2006

### Astronuc

Staff Emeritus
The way the question is worded, one cannot tell if one means circular in profile or circular in trajectory.

If circular refers to trajectory, then it would appear the charged particles are moving in a magnetic field and are thus subject to a Lorentz, $\vec{F}$,

$\vec{F}$ = q $\vec{v}\,\times\,\vec{B}$.

Use the righthand rule for the cross product. Positive charges move in one direction, negative charges move the opposite direction, and one must determine clockwise or counterclockwise.