A B C Which absorption spectrum belongs to the color of the solution shown here? A B C

A B C Which absorption spectrum belongs to the color of the solution shown here? A B C

How much visible light is transmitted through typical sunglasses? 70-80% 40-50% 10-30% 1-5%

How much visible light is transmitted through typical sunglasses? 70-80% 40-50% 10-30% 1-5% Weber-Fechner Law: eye senses brightness roughly logarithmically Optical Density OD = log10(I0/I) I0 = intensity before absorber I = intensity behind absorber Typical sunglasses: OD  0.5-1

A B Consider the complex index of refraction of a gas n = n’ - i where Which graph belongs to the real part n’ ? A B

A B Consider the complex index of refraction of a gas n = n’ - i where Which graph belongs to the real part n’ ? A B