How Does an Electron Produce Total Field in a Capacitor Setup?

[shiu1]

Homework Statement

an electron is shot in the x direction with an initial speed Vo = 3.5*10^6 m/s and accelerated through a parallel plate capacitor with a potential difference of 70V. After it travels along the x-axis for 5mm, what is the total field the electron produces, including both magnetic and electric components? your answer should give the direction and magnitude of the total vector field.

Homework Equations

B=(Uo*q*v*r)/(4π*r^2)

The Attempt at a Solution

i know i have to solve to V first. but i don't know what should i put into r. i know it's not 5 mm.

 

[diazona]

Are you sure that's the exact and complete statement of the problem? Because it definitely seems that there is some information missing. And besides, I'm not quite sure what it means by "total field".