The force on a charge moving with velocity v in a magnetic field B is half of the maximum force when the angle between v and B is?

A. 90°
B. 45°
C. 30°
D. 0°

Correct Answer:

Option C – 30°

Explanation

The force on a moving charge in a magnetic field is given by F = q V β sin θ
and this force is maximum when θ = 90o, during which sin 90° = 1: and for sinθ = 0.5, θ = 30°