What happens to the force experienced by ................................... Use it to find the direction of magnetic field in the following case.?

Question

[i]What happens to the force experienced by a current carrying conductor placed in a uniform magnetic field, when placed
(a) parallel to magnetic field?
(b) perpendicular to magnetic field?
(ii) State Flemings left hand rule. Use it to find the direction of magnetic field in the following case.

Answer 1

(i) (a) When current carrying conductor is placed parallel to magnetic field, magnitude of force is zero. 
(b) When conductor is placed perpendicular to magnetic field, magnitude of force is maximum

(ii) Fleming’s left hand rule: 
Stretch the thumb, fore finger and middle finger of left hand such that they are mutually perpendicular. If the fore finger points in the direction of magnetic field, the middle finger in the direction of current, then the thumb will point in the direction of motion or the force acting on the conductor.

According to Fleming’s left hand rule, the direction of force is perpendicular to the direction of magnetic field and current. We know that the direction of current is taken opposite to the direction of motion of electrons. Therefore, the force is directed upwards from the plane of the paper.