A magnetic field is a region in space where a magnetic force can be detected. It is created by moving electrically charged particles and can be represented by lines of force that point in the direction of the magnetic force.
Magnetic fields can exert a force on conductors, causing them to move or induce a current within them. The direction and magnitude of this force depends on the orientation and strength of the magnetic field, as well as the direction of the current within the conductor.
The right hand rule states that if you point your right thumb in the direction of the current flow within a conductor, the direction of your fingers will indicate the direction of the magnetic force exerted on the conductor.
The strength of the magnetic force on a conductor depends on the strength of the magnetic field, the length of the conductor, the current flowing through it, and the angle between the conductor and the magnetic field lines.
Magnetic fields have many practical uses, such as in electric motors and generators, MRI machines, and magnetic levitation trains. They are also used in compasses for navigation and in credit cards for data storage.