(a) Magnetic Field
The space around a magnet or a current carrying conductor in which the magnetic effect can be felt is called the maghetic field.
Magnetic Intensity
The strength of magnetic field or magnetic intensity at a point is the force experienced by a unit north pole placed at that point. The direction of the field is the direction in which this pole begins to move if free to do so.
Thus magnetic intensity is a vector quantity and has both magnitude and direction.
The S.I. unit of magnetic intensity is tesla or ampere metre.
If a magnetic pole of strength m units placed at a point where the magnetic intensity is \((\overrightarrow{\mathrm{B}})\) then it experiences a force of m \((\overrightarrow{\mathrm{B}}).\)
(b) Uniform Magnetic Field
A magnetic field is said to be uniform if a unit isolated north pole placed at different points in the field experiences the same force in the same direction.
Graphically, a uniform magnetic field is represented by equidistant and mutually parallel lines.
