In a chamber, a uniform magnetic field of `6*5G(1G=10^-4T)` is maintained. An electron is shot into the field with a speed of `4*8xx10^6ms^-1` normal to the field. (i) Explain why the path of the electron is a circle. Determine the radius of the circular orbit. `(e=1*6xx10^(-19)C, m_e=9*1xx10^(-31)kg)`.

Explanation

`r = (m_(e) v)/( e B) = (9.1 xx 10^(-31) xx 4.8 xx 10^6)/ (1.6 xx 10^(-19) xx 6.5 xx 10^(-4)) = 4.2 cm`