Final answer:
Using the magnetic force formula, the student can calculate the magnetic field's magnitude and direction causing a force on a moving proton.
Step-by-step explanation:
The student's question involves a proton moving eastward through a magnetic field and experiencing a force due south. To find the magnitude and direction of the magnetic field causing the force, one can use the formula for the magnetic force on a moving charge, which is F = qvBsin(θ), where F is the magnetic force, q is the electric charge of the proton, v is the velocity of the proton, B is the magnetic field strength, and θ is the angle between the velocity and the magnetic field. Since the force is at maximum, the angle is 90 degrees and sin(θ) is 1. The charge of the proton (q) is approximately 1.6 x 10-19 C. Using the provided velocity (v) of 4.5 x 106 m/s and the force (F) of 8.0 x 10-14 N, we can rearrange the formula to solve for the magnetic field strength (B).