Oersted Experiment showed that A current carrying wire exerts a mechanical force on a magnet , and if the magnet is free to move , this force can produce a motion in the magnet. The reverse of this is also true , that "A magnet exerts a mechanical force on a current- carrying wire , and if the wire is free to move , this force can produce a motion in the wire".
Or
When a current-carrying conductor is placed in a magnetic field , a mechanical force is exerted on the conductor, which causes the conductor to move.This is known as motor Principle.
Which forms the basis of working of electrical devices like electric motor , moving coil galvanometer.
Reason:
When a current is passed through the wire , it is pushed upwards , away from the magnet. It happens due to repulsion between the two magnetic fields : one from the magnet and one from current.
Newton's third law of motion according to which if a current - carrying wire exerts a force on a magnet , then the magnet will exert an equal and opposite force on the current carrying wire.
Experiment to demonstrate the force acting on a current carrying conductor placed in a magnetic field : the kicking wire experiment .
When a current carrying conductor is placed in a magnetic field a mechanical force is exerted on the conductor which make it move.
The direction of force acting on a current carrying wire placed in a magnetic field is
Perpendicular to that direction of current
Perpendicular to the direction of magnetic field
The maximum force is exerted on a current carrying conductor only when it is perpendicular to the direction of a magnetic field no force act on current carrying conductor when it is parallel to the magnetic field.
The direction of force on a current carrying conductor placed in a magnetic field can be reversed by reverse in the direction of current flowing in the conductor.
The direction of force on a current carrying conductor placed in a magnetic field can also be reverse by reversing the direction of magnetic field.
Fleming 's Left Hand Rule for the Direction of force :
Hold the forefinger, the centre finger and the thumb of your left hand at right angles to one another.
Adjust your hand in such a way that the forefinger points in the direction of magnetic field and the centre finger points in the direction of current, then the direction in which thumb points, give the direction of force acting on the conductor.
Magnitude of force on the conductor :
The magnitude of the force depends on the following factors :
Magnitude of the force F is directly proportional to the current flowing in the conductor.
F© I
Magnitude of the force f is directive proportional to the strength of the magnetic field.
F® B
Magnitude of the force F is directly proportional to the length of the conductor.(inside the magnetic field)
F©l
F=IBlsin© or
F = qVBsin©