Question

An electron moves in a circular path of radius 0.001m perpendicular to a uniform magnetic field. The velocity of the electron is 106ms-1. Find the magnitude of the uniform field?

Answer 1

$F_L=evB,$

$F=ma=\frac{mv^2}r,$

$F_L=F,\implies$

$B=\frac{mv}{er},$

$B=5.7~mT.$