Hello! i have a trouble with an exercise of a course of structure of matter.(adsbygoogle = window.adsbygoogle || []).push({});

Helium atoms in the excited state 2^{3}S_{1}come out from a box at v=2000 m/s and pass trough an Stern & Gerlach apparatus with dB/dz=25 T/m and lenght L=0.30m. Atoms spends 1 hour in the box and the average-time for decay is 8000s.

the questions are:

1) evaluate (number of atoms deflected with Mj=1) / (total number of atoms came out from the box)

2) evaluate the angular deflection of the component Mj=1.

So, the part 2 is very simple:

i know that the state has S=1, L=0, J=1 and using F = [tex]\mu[/tex]_{z}* dB/dz I found alpha=0.30.

But I can't understand part 1:

8000s>1hours so every atom producted come out form the box and don't decay to the ground state??

then, don't the 3 components Mj= 1, 0, -1 should have the same probability 33.3% ?

Or I should use statistical mechanics and evaluate the probability of that state in function of temperature and energy?

please help me to understand, thank you!!

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

Dismiss Notice

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!

# Stern gerlach J=1 problem

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