An electron travels in the +x-direction in a magnetic field and is acted on by a magnetic

Question:

An electron travels in the +x-direction in a magnetic field and is acted on by a magnetic force in the – y-direction.
(a) In which of the following directions could the magnetic field be oriented: (1) – x, (2) +y, (3) + z, or (4) – z? Explain.
(b) If the electron speed is 3.0 x 106 m/s and the magnitude of the force is 5.0 x 10-19N, what is the magnetic field strength?