Electromagnetic metamaterials can have a negative value for this quantity.
Electromagnetic metamaterials can have a negative value for this quantity. This value is equal to the square root of the product of a medium's permittivity and permeability. A material has two different values for this in (*) birefringence. The ratio of this value for two media is related to the ratio of sines of its namesake angles by Snell's Law. For 10 points, name this ratio of the speed of light in a vacuum to the speed of light in a medium, which is about 1.33 for water.
Electromagnetic metamaterials can have a negative value for this quantity.
index of {refraction} [or {refractive} index; or {ior}]