Chapter 27, Problem 14A

When light encounters a material, it can build up vibrations in the electrons of certain atoms that may be intense enough to last over a long period of time. Will the energy of these vibrations tend to be absorbed and turned into heat or absorbed and reemitted as light?

To determine

Whether vibration energy tend to absorb and turned into heat or absorbed and re-emitted as light (photon).

Explanation of Solution

Introduction: Vibration in material depends on temperature of the material and frequency of light incident over it.

If the incident light has energy less than the band gap energy of a material, then during collision photons unable to make electron to transit from lower to higher energy orbit due to which no absorption and reemission takes place but carrying sufficient energy to interact with the lattice of a material and set is to vibration at certain frequency. The material lattice continues to vibrate until all energy is lost on the form of heat.

Conclusion: Vibration energy tend to absorb and turned into heat when light of frequency less than energy band gap encounters material.