Distance for charge to travel through magnetic field

[bluedevil09]

Homework Statement

In the diagram below, an elementary charge (either an electron or a proton, you decide) is accelerated between two charged plates into a magnetic field. The mass of the proton = 1.67x10^-27 kg. The mass of an electron = 9.11x10^-31 kg.

D. Find the distance from the entrance point to where the charge

Homework Equations

The Attempt at a Solution

I know that the electron is going to arc up while going through the field, but I don't know how to find how much it arcs up and therefore the point at which it exits. FYI, the field is 10cm x 10cm, and starts right after the proton moves through the hole in the plate. How do I figure it out from here? Is there a way to figure out how far up the proton will move vertically? If so, I could draw a triangle and find the distance to where it exits

 

[Briggs]

If the velocity is perpendicular to the magnetic field you can find the radius of the arc by mv / |q|B

Not sure if this is the right approach but it might help.