Basic concept of Magnetism

A magnet is a material or object that produces a magnetic field. This magnetic field is invisible but is responsible for the most notable property of a magnet: a force that pulls on other ferromagnetic materials, such as iron, and attracts or repels other magnets.

Magnetic field

A magnetic field is the magnetic effect of electric currents and magnetic materials. The magnetic field at any given point is specified by both a direction and a magnitude (or strength); as such it is a vector field. Magnetic fields can be produced by moving electric charges and the intrinsic magnetic moments of elementary particles associated with a fundamental quantum property, their spin.

Magnetic field intensity

The magnetic field intensity at a point defines as the force experienced by a unit North Pole at that point. The tangent, which is drawn on the line of forces, gives the direction of magnetic field intensity. It measures in Tesla (T) or Gauss.

Magnetic pole strength

Magnetic pole strength (symbol: p) is a physical quantity used to measure the strength of the pole of a bar magnet (or a hypothetical magnetic monopole). If there is an infinitely long wire where the electric current is I, then the magnetic pole strength is defined as follows:

Magnetic moment

The magnetic moment of a magnet is a quantity that determines the torque that experience in an external magnetic field. A loop of electric current, a bar magnet, an electron (revolving around, a molecule, all have magnetic moments.

The magnetic moment may be considered to be a vector having a magnitude and direction. The direction of the magnetic moment points from the south to North Pole of the magnet. The magnetic field produced by the magnet is proportional to its magnetic moment. More precisely, It normally refers to a system’s magnetic dipole moment, which produces the first term in the multiple expansion of a general magnetic field.

The elements of terrestrial magnetism

The elements of terrestrial magnetism are

Declination