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

Two narrow beams of electrons with velocitiesvand-vare injected into an evacuated chamber along the lengthl. Each beam moves with constant speed and carries a currentI. The tendency for the beams to deflect each other through their mutual interaction is compensated by a magnetic flux densityBperpendicular to the plane containing the two electron beams so that they travel in parallel straight lines a distancedapart (d << l). Show that the ratiofof the magnetic to the electric force on each of the beams due to their mutual interaction is vε0μ0

2. Relevant equations

For two parallel currents I1 and I2 the force on a lengthlof I2 is:

F= (μ0*I1*I2*l)/2πd

3. The attempt at a solution

Using the above equation and substituting I1 = I and I2 = -I:

F= -(μ0*I^2*l)/2πd

I don't know what to do now, what is the electric force?

All I know is Coloumb's law but I thought that only applied to static charges?

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# Homework Help: Forces between parallel currents

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