## FORCE ON A CURRENT CARRYING CONDUCTOR PLACED IN A MAGNETIC FIELD

Any current carrying conductor when kept in magnetic field experiences a force.
Watch a youTube video below to observe how a current carrying wire experiences a force when kept in a magnetic field.

Video courtesy : Learn n hv fun YouTube Channel (A volunteer member of the website)

The direction of force is given by FLEMING’S LEFT HAND RULE.

ACTIVITY

1.   Take a small aluminium rod AB.
2.   Suspend it horizontally with the help of connecting wires from a stand.
3.   Place a strong horseshoe magnet in such a way that the rod is between the two poles with the field directed upwards.
4.   When current is passed in the rod from B to A, the rod gets displaced towards left.
5.   On reversing the direction of the current, the rod gets deflected towards right.

The deflection in the rod is caused by the force acting on the current carrying rod when placed in a magnetic field.
The displacement of the rod is largest (or the magnitude of the force is the highest) when the direction of current is at right angles to the direction of the magnetic field. In such a condition we can use a simple rule to find the direction of the force on the conductor.

## FLEMING’S LEFT HAND RULE

Stretch the forefinger, the central finger and the thumb of your left hand mutually perpendicular to each other. If the forefinger shows the direction of the field and the central finger that of the current, then the thumb will point towards the force or direction of motion of the conductor.

## FORCE ON A MOVING CHARGE PARTICLE IN A MAGNETIC FIELD

A current carrying conductor experiences a force when placed in a magnetic field. As current is simply flowing of charges, it implies that moving charged particles also experiences a force in a magnetic field.
The direction of the force on a moving positive charge is given by Fleming’s Left hand rule (discussed above).

Application of force experienced when placed in a magnetic field
Devices that use current-carrying conductors and magnetic fields include electric motor, loudspeakers, microphones and measuring instruments.

4.   Solenoid