Lorentz Force


Consider just an electric field E and a point charge q is exposed to that field. It experiences an electrostatic interaction with the field. Now replace the electric field E with a magnetic field B. If the point charge is stationary, there won’t be any interactions. If the charge moves at a velocity v, it creates a magnetic field around it and then it interacts with the external magnetic field.

If we introduce both the electric field and magnetic field to a point charge, there are two cases. When the charge is stationary, it would simply interact with the electric field alone. If it is moving at a velocity v, it will interact with both the electric and magnetic field, E and B respectively. Due to this interaction, the charge q experiences a force F. We call this force as the Lorentz Force.

The Lorentz force always acts perpendicular to the electric and magnetic field and is mathematically expressed as, [math]{F} = q{E} + q{v} \times {B}[/math]. The direction of the force is mnemonically deduced with the help of the right-hand rule.