Which of the following statements about a straight current-carrying wire placed in a uniform magnetic field is correct? The wire experiences?

A. maximum motor force if the current reverses its direction
B. no motor force of it is parallel to the field
C. no motor force if it is perpendicular to the field
D. a motor force with constant direction if either the current or the magnetic field is reversed

Correct Answer:

Option B – no motor force of it is parallel to the field

Explanation

The greatest force is experienced when the conductor is at right angle to the field.

I.e at perpendicular or Ø = 90°