The name is absent

Magnetic field

The magnetic field is the second component of the electromagnetic field and is
described by the vector of the magnetic induction B (known also as: magnetic
field strength or magnetic flux density) that is perpendicular to the vector of the
electric intensity E . The magnetic field acts only on moving charges and
manifests itself via electromagnetic force F_M acting upon flowing currents inside
the region where the magnetic field is distributed. From the Laplace’s law it is
known that the electromagnetic force F_M acting upon cable with electric current
i ∙ l that is inside magnetic field with magnetic induction B is equal to the vector
product of the two vectors:

(26)                 FM = i ∙ 7 × B

(27)                dFM = i ∙ dl × B

If we have magnetic dipole the direction of the vector of the magnetic induction is

from the south pole (S) to the north pole (N) inside the dipole and from N to S

outside the dipole.

The magnetic field could be excited either via changes in existing electric field E
or by flowing electric current i .

In the first case the magnetic induction is defined by the Ampere’s law (J=0):

In the second case if we have cable with current i it will generate magnetic field
with induction B whose lines have the direction of rotation of right-handed screw
when it penetrates in the direction of the current i .

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