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 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 NNN of alpha-particles scattered through an angle θ\thetaθ.
At θ=0∘\theta = 0^\circθ=0∘, NNN 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 | 1.5 |
| 90 | 2.3 |
| 60 | 2.9 |
| 45 | 3.5 |
| 25 | 4.8 |
| 0 | NNN too large |
Show that the number of alpha-particles scattered through 25∘25^\circ25∘ is about 2000 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 1.10 MeV1.10\text{ MeV}1.10 MeV is travelling directly towards a stationary nucleus of zinc-64 (3064Zn^{64}_{30}\text{Zn}3064Zn) in a head-on collision.
Explain what happens to the electric potential energy of the proton-nucleus system.
Calculate the minimum distance RRR between the proton and zinc nucleus.
