Magnetism

                                            Magnetism

History:

The Science of magnetism grew from the district of Magnesia in Asia minor for a stone called magnetite, which has ability to attract  bits of iron. Our earth is the example of natural magnet.

Orienting action in a compass needle for earth magnetic character is known us from ancient time.

Oersted first discovered that flow in a wire can create electric flow in 1980BC.

Magnetic field of a wire can be intensified  by forming it into a coil in many turns and providing into a iron core.

Magnetic Field:

Magnetic field means every point of a magnet there is a force with direction and magnitude specific to the location. Magnetic field vector is define as a B .

B=φ/A

φ means magnetic flux and A means area of a close surface.

unit of a magnetic field vector is Tesla or Webber per miter square. "wb/m^2"   

Magnetic Induction:

Magnetic induction is a method of visualizing the shape and strength of  a magnet. Magnetic inductions or magnetic field lines are same thing. Magnetic field line is a tool of visualizing the magnetic field. But they are not a real things its just a imagination.

Magnetic Flux:

Magnetic Flux means how many  magnetic field line passes through in a cross sectional area.

We can define magnetic flux using phi.

φ=∫ B.dS

So we can say that magnetic flux is an integration of magnetic field vector B and surface "S".

Unit of magnetic flux is Webber(Wb). 

Relation Between Magnetic field Vector And Magnetic Induction:

• Tangent to a magnetic field line at any point give the direction of a magnetic field vector B at any point.
• Number of magnetic inductions per unit in a cross sectional area are proportional to magnitude of a magnet field. If magnetic field lines are close enough, the magnitude of a magnetic field is larger that means value of B will much higher. on the other hand if magnetic field lines are far apart the value of B is lest.