Left-hand Rule
In certain situations, it may be useful to use the opposite convention, where one of the vectors is reversed and so creates a left-handed triad instead of a right-handed triad.
An example of this situation is for left-handed materials. Normally, for an electromagnetic wave, the electric and magnetic fields, and the direction of propagation of the wave obey the right-hand rule. However, left-handed materials have special properties, notably the negative refractive index. It makes the direction of propagation point in the opposite direction.
De Graaf's translation of Fleming's left-hand rule - which uses thrust, field and current - and the right-hand rule, is the FBI rule. The FBI rule changes thrust into F (Lorentz force), B (direction of the magnetic field) and I (current). The FBI rule is easily remembered by US citizens because of the commonly known abbreviation for the Federal Bureau of Investigation.
Read more about this topic: Right-hand Rule
Famous quotes containing the word rule:
“Charity is a cop-out so traditionally female in its apparent self-effacement that there seems resonant comfort in it. We’re no longer supposed to serve the imaginations of men who have dominated us. We are to give up ourselves instead to those whose suffering is greater than our own. Looking down is just as distorting as looking up and as dangerous in perpetuating hierarchies.”
—Jane Rule (b. 1931)