Physics
posted by BAdams .
A beam of unknow charged particles passes at right angles to the direction of magnetic field of 9.0 x 10^2 T. if the speed of the particles is 3.0 x 10^4 m/s and the force experiences by a particle is 8.64 x 10^16 N. How many electric charges are carried by one particle?

Use F = q V B to solve for the charge, q, in Coulombs.
F is the force (N) B the magnetic field (Tesla) and V is the velocity (m/s).
If they mean how many ELECTRONS (positive or negative) the particle's charge corresponds to, divide q by the electron charge, e. That will give you the number of extra or missing electrons. 
I solved and got 3.2 x 10^19 Coulombs.
What value do I divide that by? 
The electron charge, e. You should know it.
http://en.wikipedia.org/wiki/Electron
It looks like you have two electrons.