An electron moves in a circular path perpendicular to a magnetic field of magnitude $0\mathrm{.}215$ T $.$ If the kinetic energy of the electron is $2\mathrm{.}30{10}^{-19}J,$ find the speed of the electron and the radius of the circular path.

$($a$)$ the speed of the electron

$\frac{m}{s}$

$($b$)$ the radius of the circular path

$m$