The structure of atoms was deduced in the early 1900s by Rutherford and his co-workers from the scattering of alpha-particles by a very thin sheet of metal foil.
Rutherford assumed that the scattering of the alpha-particles was due to electrostatic forces. The figure below shows a detector used to record the number N N\,N of alpha-particles scattered through an angle θ\thetaθ.
At θ=0∘\theta = 0^\circθ=0∘, N N\,N was too large to be measured. The table below summarises some of the collected data.
| θ/∘\theta / ^\circθ/∘ | lg(N)\lg(N)lg(N) |
|---|---|
| 150 | 1.4 |
| 90 | 2.3 |
| 60 | 3.1 |
| 40 | 4.2 |
| 20 | 5.2 |
| 0 | N N\,N too large |
Show that the number of alpha-particles scattered through 20∘ 20^\circ\,20∘ is about 6300 times more than those scattered through 150∘150^\circ150∘.
Use the evidence from the table to explain the structure of the atom.
A proton with kinetic energy 1.8 MeV1.8\text{ MeV}1.8 MeV is travelling directly towards a stationary nucleus of silver-107 (47107Ag^{107}_{47}\text{Ag}47107Ag) in a head-on collision.
Explain what happens to the electric potential energy of the proton-nucleus system.
Calculate the minimum distance R R\,R between the proton and the silver nucleus.
