I'm setting up an experiment where I have a circular cathode releasing electrons to an outer circular anode. The tube is inside an induction coil, and when turned on, the coil provides a magnetic force on the electrons causing them to go into uniform circular motion.(adsbygoogle = window.adsbygoogle || []).push({});

The purpose of my experiment is to measure the radius of the electron beam, and use it to calculate the mass of an electron; however, the results range anywhere from a 8% to a 2000% difference. I charted a graph of radius vs magnetic field using the equation:

r = (1/B) * [tex]\sqrt{}(2Vm/q)[/tex]

r is the radius

B is the magnetic field

V is the potential difference between my cathode and anode

m is the mass of an electron

q is the charge of an electron.

this was derived from the two equations:

qv_{e}B = m(v_{e}^{2}/r)

qV = (1/2)mv_{e}^{2}

where v_{e}is the velocity of an electron

my r values are incredibly small (fractions of a cm) when I use this equation, and I'm all out of ideas. Can anyone see the flaws in my reasoning?

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# Help calculating the mass of an electron

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