Final Prep Answers

Chem 155 Final review topics and questions:
A silica – SiO 2 (other acceptable: sapphire, calcium fluoride)
B zinc selenide – ZnSe (also germanium, silicon and potassium bromide)
12. Give an example of a light source that is operative in (A) the UV-Visible and Near
IR, and (B) the IR regions of the EM spectrum. For each, give an example of a
line source and a continuum source.
A
UV, VIS or NIR line source hollow cathode lamp or laser
UV, VIS or NIR continuum source tungsten halogen or Xe-arc lamp
B
- IR continuum source Nernst glower
13. Draw a simple schematic of a laser and label the important parts.
14. What processes are involved in loss and gain in a laser light cavity. Name them
and give a short equation showing photons and states to indicate your answer.
15. Draw an energy level diagram for a 4-level laser and indicate the levels involved
in the lasing transition.
16. What must be the case if laser radiation transiting the laser cavity is to be
amplified by stimulated emission rather than attenuated