A Beam of Electrons Moving at a Speed of 8

A beam of electrons moving at a speed of 8 × 10⁴ m/s is undeflected when it passes through an electric field of 5 N/C perpendicular to its path and a magnetic field that is perpendicular to its path and also to that of the electric field. Calculate the strength of the magnetic field.

A) 1.60 × 10⁴ T
B) 6.25 × 10^-5 T
C) 7.81 × 10^-10 T
D) 3.13 × 10^-5 T
E) 1.25 × 10^-4 T