[r-kaede]

its part of the physical chemistry module, i know the formula i just want to know if its correct or not:

Calculate the mean time a photon spends inside a laser cavity of length
1.5 m, if the product of the reflectivities of the end mirrors, R1R2, is 95%.  
 
Speed of light, c = 3.00 x 10^8 m s-1

answer:

t= 2L/(C'(1-R1R2))
 = (2x1.5m)/(3.00x10^8(1-0.95))
 =..(forgot to bring my calculator, too lazy to go up to my room, but will i get the right answer from this equation?)


is this right? because the mark for the question is 20% and it seem too easy.

[Enthalpy]

I'd have done it the same way.

Suspected world record at the interferometers of gravitation waves detectors:
http://en.wikipedia.org/wiki/LIGO
http://en.wikipedia.org/wiki/VIRGO