A complex version of this quantity adds i plus the extinction coefficient, while one formula sets its square equal to a rational equation in terms of the coefficients B1 through 3 and C1 through 3.
One paradox concerning this quantity, in which one calculation places it in the numerator but a formula for an identical quantity places it in the denominator, was raised by Peierls. A complex version of this quantity adds i plus the extinction coefficient, while one formula sets its square equal to a rational equation in terms of the coefficients B1 through 3 and C1 through 3. This quantity can be negative in artificial metamaterials. The arctangent of the ratio of this quantity for two materials gives Brewster's angle. Along with the sines of the angle of incidence and this quantity's namesake angle, it is used in Snell's Law. For 10 points, name this quantity that describes the speed of light in a medium, the namesake of a certain light-bending effect.
One paradox concerning this quantity, in which one calculation places it in the numerator but a formula for an identical quantity places it in the denominator, was raised by Peierls.
 index of refraction [prompt on n]