What is B-field: Definition and 106 Discussions

A magnetic field is a vector field that describes the magnetic influence on moving electric charges, electric currents, and magnetic materials. A moving charge in a magnetic field experiences a force perpendicular to its own velocity and to the magnetic field. A permanent magnet's magnetic field pulls on ferromagnetic materials such as iron, and attracts or repels other magnets. In addition, a magnetic field that varies with location will exert a force on a range of non-magnetic materials by affecting the motion of their outer atomic electrons. Magnetic fields surround magnetized materials, and are created by electric currents such as those used in electromagnets, and by electric fields varying in time. Since both strength and direction of a magnetic field may vary with location, they are described as a map assigning a vector to each point of space or, more precisely—because of the way the magnetic field transforms under mirror reflection—as a field of pseudovectors.
In electromagnetics, the term "magnetic field" is used for two distinct but closely related vector fields denoted by the symbols B and H. In the International System of Units, H, magnetic field strength, is measured in the SI base units of ampere per meter (A/m). B, magnetic flux density, is measured in tesla (in SI base units: kilogram per second2 per ampere), which is equivalent to newton per meter per ampere. H and B differ in how they account for magnetization. In a vacuum, the two fields are related through the vacuum permeability,




B


/


μ

0


=

H



{\displaystyle \mathbf {B} /\mu _{0}=\mathbf {H} }
; but in a magnetized material, the terms differ by the material's magnetization at each point.
Magnetic fields are produced by moving electric charges and the intrinsic magnetic moments of elementary particles associated with a fundamental quantum property, their spin. Magnetic fields and electric fields are interrelated and are both components of the electromagnetic force, one of the four fundamental forces of nature.
Magnetic fields are used throughout modern technology, particularly in electrical engineering and electromechanics. Rotating magnetic fields are used in both electric motors and generators. The interaction of magnetic fields in electric devices such as transformers is conceptualized and investigated as magnetic circuits. Magnetic forces give information about the charge carriers in a material through the Hall effect. The Earth produces its own magnetic field, which shields the Earth's ozone layer from the solar wind and is important in navigation using a compass.

View More On Wikipedia.org
  1. G

    B-field produced by a spiral coil

    Howdy I'm having a ton of trouble with this question Basically I have a spiral coil running around the z-axis with radius 'a' height '2b' and pitch 'c'. The point (x,y,z) = (a,0,0) is on the spiral and n = 2b/c (that's the number of turns on the spiral). There's a steady current running...
  2. T

    How Is Potential Difference Affected When a Loop Exits a Magnetic Field?

    If there's a loop exiting a B-field, where half of it is in the b-field and half of it is out. How would a potential difference be found in the wire? I said that V = BLv, (where L is the height of the loop, disregarding the width) and found V to be 3v. Although, there is one resistor on the...
  3. T

    Potential difference between plates in a B-Field?

    How is potential difference found between two plates in a B-field? Any help is greatly appreciated.
  4. turin

    Explaining B-Field of N-Star: How Neutron Stars Have Magnetic Fields

    Can someone explain to me how a neutron star (I'm assuming that it has no charge even on the microscopic level) can have a magnetic field? And even if I assume that there is some residual charge left after the collapse, how could the magnetic poles point in significantly different direction...
  5. tandoorichicken

    Calculating Currents in Parallel Wires: Exploring B-Field Repulsion

    Two parallel wires repel each other with a force per length of 1.00*10^-3 N/m when spaced a distance of 2.50 cm apart. If one wire has a current of 100A, what is the current in the other wire? Don't know where to start this one.
  6. P

    Estimating B-Field Required to Levitate a Train

    Hey! I am trying to get a rough estimate for the B-field (from a electromagnet) required to levitate a train. Assuming the train is of mass M, the force required to lift it and hold it at a distance D would have to equal M x g right? But how do i estimate the b-field an electromagnet...
Back
Top