An Electron Is Moving at a Speed of 12 ×

Multiple Choice

An electron is moving at a speed of 12 × 10⁶ m/s at an angle of 30° with respect to a uniform magnetic field of 8.0 × 10^-4 T.What is the radius of the resulting helical path? (m_e = 9.11 × 10^-31 kg,q_e = 1.6 × 10^-19 C)

A) 2.1 cm
B) 3.7 cm
C) 4.3 cm
D) 8.5 cm