A proton having an initial velocity of 21.3i Mm/s enters a uniform magnetic field of magnitude 0.320 T with a direction perpendicular to the proton's velocity. It leaves the field-filled region with velocity -21.3j Mm/s.

(a) Determine the direction of the magnetic field. i -j k -i -k j

(b) Determine the radius of curvature of the proton's path while in the field. m

(c) Determine the distance the proton traveled in the field. m

(d) Determine the time interval for which the proton is in the field.