A Proton with Velocity 2

Multiple Choice

A proton with velocity 2.0 × 10⁵ m/s enters a region where a uniform magnetic field of 0.30 T is present. The proton's velocity makes an angle of 60° with the magnetic field. What is the pitch of the helical path followed by the proton? (The "pitch" is the distance traveled parallel to the magnetic field while making one complete revolution around a magnetic field line.)

A) 0.250 m
B) 0.077 m
C) 0.022 m
D) 0.140 m
E) 0.055 m