The Radius of the Orbit of an Electron Moving with a Speed

Multiple Choice

The radius of the orbit of an electron moving with a speed of 10⁸ m/s perpendicular to a magnetic field of 5.0 $\times$ 10^-3 T is approximately

A) 1.1 m
B) 0.11 m
C) 0.34 m
D) 0.011 m
E) 8.9 m