As we know, if we have a group of atoms at a moment N(t) in an exited state, it will exponentially decrease according to the relation:(adsbygoogle = window.adsbygoogle || []).push({});

N(t)=N(0) exp(-At)=N(0) exp(-t/(tau))

Where A is the Einsteins constant for the spontaneos emission,

In my book they defined tau in the relation I explained in PDF

Can Any one tell me WHERE DID HE BROUGHT THE SECOND RELATION FROM????

Thanks for reading

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Life time in spontaneous emission for laser

Loading...

Similar Threads for Life spontaneous emission |
---|

I Why don't absorption and emission spectra "cancel out"? |

A Reflection or emission of a photon |

I Rotational Spectra |

**Physics Forums | Science Articles, Homework Help, Discussion**