Electromagnetism Physics

PHYSICS

                         ELECTROMAGNETISM

The electric current produces magnetic field.this affect of electric current is called electromagnetic.......

MAGNETIC FIELD DUE TO CURRENT IN A LONG STRAIGHT WIRE.:-

Consider a thick copper wire passing through the hole of card board.Number of compass needles are placed along the wire in the form of circle with centre as copper wire..when there was no current than all the needles wire in N-S direction
when current is passed all the needles set themselves tangential by to the circle.when direction of current is reversed.when current is stopped, the compass needles again set themselves in N-S direction....

CONCLUSION:-

1.Magnetic field is setup when current passes through the conductor....
2.Magnetic lines of force are circular and their direction depends upon the direction of current....
3.The magnetic field remains only as long as the current is present in the wire ...
4.The strength of field is stronger near the wire and becomes smaller when distance from the wire increases.
The direction of magnetic field due to current is determined by "right hand rule"...

RIGHT HAND RULE:-

Grip the wire in right hand in such a way that stretched thumb points in the direction of flow of current, the finger of the right hand encircle the wire in the direction of magnetic field....

FORCE ON A CURRENT CARRYING CONDUCTOR IN A UNIFORM MAGNETIC FIELD :-

When a current carrying conductor is placed in a magnetic field, it will experience a force due to interaction between two magnetic field .It can be seen by the following experiment ...

Consider a copper rod is placed on a pair of copper rail where magnetic field "B" is vertically upward ...
When current is passed throught the copper rod, the rod roll on the rail from figure it is clear that the force on a conductor is always at right angles to plane which contains the rod and the direction of magnetic field...
The magnitude of force acting on the conductor depends upon the following factors.
1. The magnetic force is directly proportional to sin@ where @ is angle between 'B' and lenght of conďuctor 'L' ...