Question

A particle of charge 2.5x10(^-6)C is moving at 1000 m/sec in a direction 30 degrees North of east. At the location of the particle the magnetic field has size 0.2 T. The particle is experiencing an instantaneous magnetic force (due to this sheild) of 1.71x10(^-4) newtons directed vertically down. The size of the angle A (in deg) between the velocity and the magnetic field at the location of the particle is most nearly:

0
12.6
15.9
17.1
20.0
24.1
28.3
70