Why Does Glass with Metal Coating Appear Red on One Side and Blue on the Other?

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SUMMARY

The discussion centers on the optical phenomenon observed in a glass piece with a metal coating, where it appears red from the metal side and blue from the opposite side. This effect is attributed to the photoelectric effect, where the metal's work function allows blue photons to transmit through while reflecting red photons. The wavelengths involved are 700nm for red and 500nm for blue, indicating a cutoff frequency that affects light transmission and reflection based on energy levels.

PREREQUISITES
  • Understanding of the photoelectric effect
  • Knowledge of light wavelengths (700nm for red, 500nm for blue)
  • Familiarity with dispersion relations in optics
  • Basic principles of metal coatings and their interaction with light
NEXT STEPS
  • Research the photoelectric effect and its implications on light transmission
  • Explore the concept of cutoff frequencies in optical materials
  • Study dispersion relations and their role in light behavior
  • Investigate the properties of metal coatings and their effects on light reflection and transmission
USEFUL FOR

Physics students, optical engineers, and anyone interested in the interaction of light with materials, particularly in understanding color perception in coated glass.

wormhole
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Hi

the problem i have sounds something like that:

there is a piece of glass with metal cover(on one side) in vacuum.
light incident on metal surface.
if you look at the glass from the metal surface side it appears red but when you look at it from other side it appears blue.
given wave length of red is 700nm and blue 500nm.

then there is two questions:
1. explain the phenomena
2. estimate metal surface width

i find it difficult to explain this phenomena...
right now my idea is that there is some cuttoff frequency(derived from dispersion relation) corresponding approximatly to red wavelength.. so that any light with wave length>~700 is reflected.
but i don't know what to say about the blue color on opposite side

can someone point me in the right direction?
thanks a lot
 
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Sound to me like the photoelectric effect. If the metal has a work function equal to the energy of a single blue photon, then it may transmit blue photons onto the glass side, while it will reflect all the red, less energetic, photons.
 

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