# Atomic physics question

1. Dec 8, 2004

### briton

Describe briefly one piece of evidence for each of the following statements.

Each part is worth 4 marks, so I would really appreciate if someone could reply with some slightly easy to understand, but quite detailed points.

Thankyou.

2. Dec 8, 2004

3. Dec 8, 2004

### dextercioby

1.For the first part,i guess that,historically,the first to get a value for the atom radius of the H atom was Niels Bohr in 1913.Yet,he said that there wasn't only one value for this number,but an infinity.It's the famous eq.of radial distance (between the proton and the electron) quantization.
In the terms of QM,the concept of "atomic radius" loses segnificance,but one can define it as the distance to the nucleus at which the probability of finding the lousy electron (for the H atom) is maximum.For more atoms,it's not that simple,since it wouldn't work.For the H atom,that number is exactly the first Bohr radius.
2.The Rutherford scattering model should provide u with a radius of the scattering nucleon.Apply the law of energy conservation.Assume the nucleon is fix (has amuch greater mas than the incoming alpha particle) and the potential of scaterring is Coulomb type.

Daniel;
EDIT:I KNEW IT WOULD HAVE SOMETHING TO DO WITH SIR ERNEST RUTHERFORD :tongue2:

Last edited: Dec 8, 2004