# Moment of Inertia of dysprosium-160

1. Apr 4, 2016

### Guessit

1. The problem statement, all variables and given/known data
The nucleus dysprosium-160 (containing 160 nucleons) acts like a spinning object with quantized angular momentum, L2 = l(l + 1) * h_bar2, and for this nucleus it turns out that l must be an even integer (0, 2, 4...). When a Dy-160 nucleus drops from the l = 2 state to the l = 0 state, it emits an 87 keV photon (87 ✕ 103 eV).

h_bar = reduced planck's constant
2. Relevant equations

Kinetic Energy = L2 / 2I , where I is the moment of inertia

3. The attempt at a solution

Change in KE = Change in L2 / 2I = 5h_bar2 / 2I
Substituting and solving for I gave me around 2*10-54 which apparently isn't the answer.
Am I using the wrong formula?

edit: rookie mistake, Change in KE = 6 * h_bar.... not 5.

Last edited: Apr 5, 2016
2. Apr 5, 2016

### Simon Bridge

Show your reasoning. Where does the energy come from? Where does it go?
How did you account for the energy of the photon, for instance?
Check other sources of mistakes - like the value of I and the units.