At one instant an electron $($charge $=1\mathrm{.}6$ x $1019$ C$)$ is moving in the xy plane, the components of its velocity being vx $=5\mathrm{.}0$ x $105$ m$/$s and vy $=3\mathrm{.}0$ x $105$ m$/$s$.$ A magnetic field of $0\mathrm{.}80$ T is in the positive y direction. At that instant the magnitude of the magnetic force on the electron is: