A cosmic-ray electron moves at 7.5 × 10 6 m/s perpendicular to Earth's magnetic field at an altitude where the field strength is 1.0 × 10 −5 T. What is the radius of the circular path the electron follows? Negative charge of an electron = 1.6 × 10^−19 C Mass of an electron = 9.1 × 10^−31 kg 4.35 m 3.45 m 6.50 m 7.50 m