Questions for physics assignment for cs

1. explain einsteins coefficiant?
2.basic principles of laser
3.working principle ruby laser
4.working principle helium neon laser
5.explain breifly application of laser
6.holography?recording reconstruction.process in holography?application?
7.optical fibre ?explain application?advantages over conventional transmission lines ?
8.semiconductor injection laser?
9.explain spontaneous emission,stimulated emission
10.explain pumping,metastable level,population inversion..