There are a few forms of this rule, and it can be applied in many ways. Originally, it was a trick for right-handed coordinate systems to determine the direction of the magnetic field surrounding a long, straight wire carrying a current. Note that the magnetic field lines form circles around the wire.
This is how it works. Orient your right hand so that your thumb is along the direction of the current. The four fingers wrap in the direction of the magnetic field.
This has immediate application for determining the orientation of the z-axis basis unit vector,
The right hand rule applies to the flows of positive charges. If negative changes are flowing, simply use your left hand. The right hand rule can also be used to find the force induced by the presence of a magnetic field and the velocity of a particular particle. When a charge is placed in a magnetic field, that charge experiences force if:
- the charge is moving relative to the magnetic field,
- the charge's velocity has a component perpendicular to the direction of the magnetic field
The following video will explain these two applications of the right hand rule