Every force field (be it gravitational, electric, magnetic, etc) make its presence felt by the fact that it acts with a force on a so called test object. In fact the intensity of the field is defined as the force with which the field is acting on the unity test object. For example in the case of gravitational field its intensity `Gamma` is given by
`Gamma(R) = G*M/R^2 (= F/m)`
where the force on test object is `F=m*Gamma =G*(mM)/R^2`
In the case of magnetic field its intensity is derived from the force exerted on a wire of length `L` in which flows a current `I=1 A`
`B(= F/I) =mu*L`
Because presence of a field means as shown above, presence of a force, the field can do work on a body that moves in the filed (of course the body need to have certain proper characteristics, like mass in the gravitational field and current through it, or electrical charge in the magnetic field). As by its definition, work done means variation of energy between final and initial states. Therefore each field means an associated energy to each point in the space that it fills.
For gravitational field this is just the potential energy as we know it very well
`E_G =E_p (=m*g*R) =m*(G*M/R^2)*R =m*(G*M/R) =m*U`
For magnetic field the energy is defined as
where `V` is the volume of space for which the energy is defined.
Hence magnetic energy is the energy that comes from the presence of a magnetic field in the space. The existence of this energy associated with each point in space implies the capacity of magnetic field to do work on a body that is electrically charged and moves in the field, or through which an electric current flows.
i dont understand anything wat was u said about that pls make sure that it is in easy lang....
- Magnetic energy is energy generated due to magnetic field. When a iron place is kept in magnetic field, it gets attracted due to magnetic energy.
The potential energy of a magnet of magnetic moment in a magnetic field.it also can be describe as the energy in a magnet.A magnet is rubbed back and forth to create that energy.