At some point in our lives we have heard that if we place a magnet next to a compass, it will get disoriented. This is due to the magnetic interaction between the compass and the magnet.
The magnet establishes a magnetic field in the space around it, which we didactically represent by lines of induction as in the electric field. Like the electric field, the magnetic field is a vector, that is, a mathematical entity that has a magnitude, direction and sense.
By definition, the magnetic field vector 
at each point it has a tangent direction to the field line and the same direction as it. Therefore, the magnetic field has its orientation represented by an arrow placed at that point.
Uniform Magnetic Field.
It is the region where the electric field vector is always the same. In this region, the lines representing the magnetic field are parallel, equally spaced and oriented.
Magnetic force.
From electrostatics, we know that a test charge placed in a region of an electric field is subjected to the action of an electric force
, where is the electric field vector 
at a point P.A charge placed in a magnetic field is subjected to a magnetic force. Being
the magnetic induction vector at a point P where the load passes what with speed v. And let Ө be the angle formed between v and 
, the magnetic force is perpendicular to the field 
and at speed v.The intensity of the magnetic force is directly proportional to what, a
, a v and the if not.
Because the magnetic force is perpendicular to velocity, it is a centripetal resultant. This means that the magnetic force changes the direction of charge velocity.
By Kléber Cavalcante
Graduated in Physics
Brazil School Team
See more!
Magnetic Flux and Faraday's Law
The Earth's Magnetic Field
Lenz's Law
Electromagnetism - Physics - Brazil School
Source: Brazil School - https://brasilescola.uol.com.br/fisica/o-vetor-campo-magnetico.htm
