(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Determine the required magnetic field to give an electron deflection angle of θ=90deg. The other variables (such as Rd, Re, and the electron energy in keV) are currently dummy variables such that this problem will initially be solved symbolically.

2. Relevant equations

(1) F=q(v x B)

(2) F = qvbsinθ

(3) QBR = p

3. The attempt at a solution

Using the following figure (apologies for poor paint skills), I've taken the cross product of (v x B), recognizing that v_{x}= 0, B_{y}= B_{z}= 0. This gives me that v x B = (v_{z}B_{x})y - (v_{y}B_{x})z where y and z are unit vectors.

Edit: Apologies; I seem to be awful at remembering to attach photos, files in e-mail, etc. Here's the figure: http://i.imgur.com/V5TN9.png

I am having trouble fitting the cross product to another equation to yield any kind of results. Let me know if I should do more work (I've been reading through Griffith's Intro to Electrodynamics for about two hours now trying to make any headway).

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# Cyclotronic motion problem.

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