FORCE ON A CURRENT CARRYING CONDUCTOR PLACED IN A MAGNETIC FIELD

When current flows through a conductor placed in a strong magnetic field, it experiences a force in the upward direction i-e direction perpendicular to the magnetic field. The direction of the force experienced by a current carrying conductor is given by Fleming’s Left Hand Rule.

Fleming’s Left Hand Rule:  According to Fleming’s left hand rule, the thumb shows the direction of force, index finger shows the direction of the magnetic field and the middle finger shows the direction of the current flowing through the conductor. Directions of force, magnetic field and current all are mutually perpendicular to each other.

Factors on which the force acting on a current carrying conductor depends:

·         Strength of the magnetic field.

F α B

·         Strength of electric current

F α I

·         Length of the conductor

F α l

                Therefore, we can say that F = BIl

            Or        B = (formula for field strength)

Magnetic field strength: the magnetic field strength (B) is defined as the force acting per unit current per unit length of a conductor placed perpendicular to the direction of the magnetic field. The SI unit of magnetic field is TESLA (T).

                                                1 T = 1 NA^-1m^-1

[When I = 1 A, l = 1 m and B = F]

NOTE: A current carrying conductor placed perpendicular to the magnetic field experiences a maximum force. No force is experienced by a current carrying conductor when placed parallel to the magnetic field.