A Proton Having a Speed of 3

Multiple Choice

A proton having a speed of 3.0 × 10⁶ m/s in a direction perpendicular to a uniform magnetic field moves in a circle of radius 0.20 m within the field. What is the magnitude of the magnetic field?
(e = 1.60 × 10^-19 C, m_proton = 1.67 × 10^-27 kg)

A) 0.080 T
B) 0.16 T
C) 0.24 T
D) 0.32 T
E) 0.36 T