A magnetic field is a region in which a moving charge or a current-carrying conductor will experience a force when it is placed in it. Hence it is a field of force.
Magnetic fields are produced and experienced by moving charges. Magnetic field will not have any effect on a stationary charge.
Magnetic fields can be represented by field lines. (or lines of force)
- They show the direction of the magnetic field. (They emerge from the N pole and enter the S pole)
- The closeness of the lines is an indication of the strength of the field
- Parallel field lines indicate that the field is uniform
- The field lines NEVER cross or touch one another
- The field lines have arrows drawn on each of them
Diagram by TStein. Link: http://en.wikipedia.org/wiki/File:Magnetic_field_near_pole.svg. Available under the Creative CommonsAttribution-Share Alike 3.0 Unported license.
Magnetic field lines of a permanent magnet can be obtained by using a plotting compass.
- Under the influence of the magnetic field of the permanent magnet, the compass needle will align itself in the direction of the resultant magnetic field at that point.