The table below lists four surfaces, each characterized by an average root-mean-square (rms) height variation hrms measured over length scales comparable to the wavelength range 400nm≤λ≤700nm of visible light.
Surface
hrms
(a) For each surface, classify whether the dominant reflection of visible light is expected to be primarily specular, primarily diffuse, or a mixture of both. Provide a brief justification for each classification based on the information given.
(b) Rank the four surfaces from brightest to dimmest when viewed from the specular reflection direction. Explain the reasoning behind your ranking.
(c) Describe how the appearance of Surface C (frosted glass) would change if the illumination were switched to monochromatic near-infrared light of wavelength 1.0μm while all other conditions remain the same. Justify your answer in terms of the roughness-to-wavelength ratio.