opaque and transparent

[Ankit Gupta]

why do light passes through transparent material but not opaque even both are solids ?

[swansont]

It depends on the electron structure of the material. Transparent materials don't have allowed transitions in the visible part of the spectrum.

[Ankit Gupta]

would you please explain it further more

[between3and26characterslon]

Glass is transparent to visable light but relatively opaque to UV, This is because the electrons sorrounding atoms can only have certain energies and therefore the difference between energies is a specific amount. So in glass UV radiation has exactly the right amount of energy to cause an electron to jump a whole number of energy levels so it CAN be absorbed. Visable light however has only sufficient energy to cause an electron to jump a fraction of an energy level and, as this is not possible, it CANNOT be absorbed. So different materials are either transparent or opaque to different wavelengths of light depending on the allowed electron transitions in that material