Oersted ’ s Experiment
A magnetic field is produced in the surrounding of any current carrying conductor . The direction of this magnetic field can be obtained by Ampere ’ s swimming rule .
SI unit of magnetic field is Wm -2 or T ( telsa ).
The strength of magnetic field is called one tesla , if a charge of one coulomb ,
when moving with a velocity of 1 ms -1 along a direction perpendicular to the direction of the magnetic field experiences a force of one newton .
1 tesla ( T ) = 1 weber metre -2 ( Wbm -2 ) = 1 newton ampere -1 metre -1 ( NA -1 m -1 ) CGS units of magnetic field are called gauss or oersted . 1 gauss = 10 -4 tesla .
Maxwell ’ s Cork Screw Rule
If a right handed cork screw is imagined to be rotated in such a direction that tip of the screw points in the direction of the current , then direction of rotation of thumb gives the direction of magnetic line of force .
The conventional sign for a magnetic field coming out of the plane and normal to it is a dot i . e .,
The magnetic field perpendicular to the plane in the downward action is denoted by ®.
Ampere ’ s Swimming Rule
If a man is swimming along the wire in the direction of current his face turned towards the needle , so that the current enters through his feet , then north pole of the magnetic needle will be deflected towards his left hand .
Magnetic Field
The space in the surrounding of a magnet or any current carrying conductor in which its magnetic influence can be experienced .