Chapter 27, Problem 12A

Will glass be transparent to light with frequencies that match its own natural frequencies?

To determine

Transparency of a glass when incident light frequency matches with glass natural frequency.

Explanation of Solution

Introduction: Resonance is very peculiar phenomena that occurs when natural frequency of vibration of the material matches with the external frequency applied to the system and hence system vibrates with maximum possible amplitude.

The particle responsible for vibrations in a material is called phonon. When light of suitable frequency falls on a glass whose natural frequency of vibration matches with the frequency of incident light leads to resonance i.e. maximum amplitude of vibration. In this situation, photon is absorbed by the material and leads to loss of energy in the form of heat because energy carried by photon is not sufficient to make transition of electron from lower to higher excited state or vice-versa. Therefore glass will be opaque to incident light.

Conclusion: Glass will be opaque to light whose frequency matches with the glass natural frequency.