# Electric Motors And Generators/Magnetic Field Concepts

## Magnetic Field Concepts

An electromagnetic field is a region of space in which electrical charges experience forces. The classical definition of the electromagnetic field is given by the following equation

${\displaystyle \mathbf {F} =q\mathbf {E} +q\mathbf {v} \times \mathbf {B} }$

What this equation states, is that an electrical charge of size q experiences a force when in the presence of an electric field denoted by E. Furthermore if the charge is moving, with velocity v, it will experience a further force if in the presence of a magnetic field denoted by B. Therefore the force on a electric charge defines what the electric and magnetic fields are in a given region of space. Without the presence of a charged particle it could never be known what their magnitudes or directions were.