An electron of mass, $m,$ initially moving horizontally to the right at speed $v$ enters a region of uniform magnetic field, vec$(B),$ pointed $[$DOWN$]$ at right angles to the plane in which the electron is moving. In order to determine the radius of the electron's path in the uniform magnetic field, provide a system diagram $1A,$ the concept$($s$)$ involved $1A,$ the steps required $2A,$ the equations to be used $[1$A$]$ and a sketch of the proton's path in the magnetic field $[1$A$].$ Do not try to solve.