When at rest a proton experiences a net electromagnetic force of magnitude 9.4 x 10-13 N pointing in the positive x direction. When the proton moves with a speed of 1.3 x 106 m/s in the positive y direction the net electromagnetic force on it decreases in magnitude to 9.2 x10-13 N, still pointing in the positive x direction.
B: Find the magnetic field
(__0__ i + __0__ j + ____ k) T