Magnetic field

Magnetic Field

A Magnetic field is a vector field that describes the magnetic influence on moving electric charges, electric currents, and magnetic materials. A charge that is moving in a magnetic field experiences a force perpendicular to its own velocity and to the magnetic field. A material that is placed in a magnetic field can become magnetized.

Overview

Magnetic fields surround electric currents, magnetic dipoles, and changing electric fields. They have both a direction and a magnitude, making them vector fields. The direction of the magnetic field at any point is parallel to the direction of nearby field lines, and the local density of field lines can be made proportional to its magnitude. Magnetic fields are produced by moving electric charges and the intrinsic magnetic moments of elementary particles associated with a fundamental quantum property known as their spin.

Magnetic Field and Magnetic Forces

Magnetic fields cause forces to act on moving charges and current-carrying wires. The force exerted on a moving charge is perpendicular to both the velocity of the charge and the magnetic field. This force can be calculated using the Lorentz force law.

Magnetic Field Lines

Magnetic field lines are a visual tool used to represent magnetic fields. They describe the direction of the magnetic force on a north monopole at any given position. Because monopoles are not found to exist in nature, we also discuss magnetic field lines in terms of lines of force.

Earth's Magnetic Field

The Earth's magnetic field, also known as the geomagnetic field, extends from the Earth's interior out into space, where it interacts with the solar wind, a stream of charged particles emanating from the Sun. It is approximately a dipole on Earth's surface.

Measurement of Magnetic Field

The strength of a magnetic field is usually measured in teslas, the SI unit. However, in some contexts, the gauss is used instead.

See Also

• Electromagnetic field
• Magnetism
• Maxwell's equations
• Electromagnetism

References

Magnetic field Resources
Latest articles Most recent articles Ongoing trials	Wikipedia