|MadSci Network: Physics|
B = žo (4/5)3/2 N I /A žo is the permeability of free space N is the number of turns in the Helmholtz coil I is the coil current A is the radius of the coil Theory A charged particle (qo) moving with velocity v in a magnetic field B feels the force (Called the Lorentz Force): F = qov x B. Since v and B are perpendicular, and since the charged particle in an electron, replacing qo with e => FB = evB. The B field is uniform therefore the electron moves in a circular trajectory. Also, since the electron moves in a circle with constant v , it undergoes Uniform Circular Motion => a centripetal force (Fc = m v2 / R) . Setting Fc = FB => m v2 / R = evB => m v = e B R 5.1), where R is the radius of the electronís circular trajectory.
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