Force on a current carrying conductor in a magnetic field

Question 1 Define Fleming’s left hand rule?

Force on a Current carrying Conductor in a Magnetic Field

When a current carrying conductor is placed in a magnetic field, the conductor experiences a force.

(1) Take a small aluminium rod. Using two connecting wires suspend it horizontally from a stand.

(2) Place a strong horse-shoe magnet in such a way that the rod lies between the two poles with the magnetic field directed upwards. For this the north pole of the magnet vertically below and south pole vertically above the aluminium rod.

(3) Connect the aluminium rod in series with a battery, a key and a rheostat.

(4) Now pass a current through the aluminium rod from end A to end B.

(5) It is observed that the rod is displaced towards the left. The rod gets displaced.

(6) Reverse the direction of current flowing through the rod and observe the direction of its displacement. It is now towards the right.

Conclusion

(1) Force is exerted on current carrying Al rod when it is placed in a magnetic field.

(2) Direction of force is reversed when direction of current through conductor is reversed.

(3) If the direction of magnetic field is reversed, the direction of force gets reversed.

Fleming’s left Hand Rule

Stretch the left hand such that the thumb, first finger and central finger are mutually perpendicular to each other. If the first finger points in direction of magnetic field and central finger points in direction of current, then the thumb will point in direction of force.