10 minutes maximum! Can you do it in 5?
1-4. These questions are about Rutherford scattering as observed in Geiger and Marsden's experiment.  

1. What was the particle and target material in this experiment?

 Incident particle Target
A
 alpha gold foil
B
 alpha uranium nuclei
C
 beta gold foil
D
 beta uranium nuclei
2. Rutherford estimated the size of the nucleus using 'closest approach' calculations. At the point of closest approach, which of these statements is true?
  • A. gravitational potential energy of system = potential energy of system due to coulomb repulsion
  • B. initial particle kinetic energy = gravitational potential energy of system
  • C. initial particle kinetic energy = potential energy of system due to coulomb repulsion
  • D. potential energy of system due to coulomb repulsion = final particle kinetic energy

3. Rutherford predicted that, for particles with the same initial energy, the relative intensity of scattered particles would decrease as the scattering angle increased as shown here.

predicted Rutherford Scattering graph

However at high energies, the scattering pattern deviated from Rutherford's predictions. Which of the following graphs best shows this deviation?

  

Deviation from Rutherford scattering

4. The deviation from the expected pattern provides evidence for...

  • A. nuclear energy levels.
  • B. neutrinos.
  • C. the weak nuclear force.
  • D. the strong nuclear force.

5. A helium nucleus consists of 2 protons and 2 neutrons. Which of the following will have a radius of approximately double that of a helium nucleus?

  • A.
8 Be
4
  • B.
 16 O
8
  • C.
 32 S
16
  • D.
 128 Te
52

6. The calculation in question 5 relies on the fact that ...

  • A. nuclear densities are approximately the same for all nuclei.
  • B. Most nuclei have similar numbers of neutrons and protons.
  • C. Most nuclei have more neutrons than protons.
  • D. All atomic nuclei have attractive and repulsive forces acting.

Q7-8. This diagram shows electron energy levels in a hydrogen atom. Only the first 4 energy levels are shown.

Emission or absorption of a photon is associated with an electron jump between energy levels.

 

 Hydrogen electron energy levels

(Not to scale -approximate energy level values).

7. Which of the following can be used to calculate the value of the energy released when an electron drops from n=3 to n=1?

  • A. ${{13.6} \over {9}} eV$
  • B. ${{13.6} \over {3}} eV$
  • C. ${{8 \times 13.6} \over {3}} eV$
  • D. ${{8 \times 13.6} \over {9}} eV$

8. A transition from n=4 to n=2 emits a photon of blue light of wavelength close to 500nm. Which of the following transitions would emit visible red light, of approximately 650 nm wavelength?

  • A. 5 to 2
  • B. 4 to 3
  • C. 3 to 2
  • D. 2 to 1

9+10. Electron orbits are quantised in the Bohr model of the atom, where $mvr = {{nh} \over {2\pi}}$.

9. What is the quantity mvr in this equation?
  • A. angular velocity
  • B. angular momentum
  • C. angular spin
  • D. angular acceleration

10. What is the change in mvr when an electron drops from n=4 to n=2?

  • A. ${h} \over {2\pi}$
  • B. ${h} \over {\pi}$
  • C. ${{2h} \over {\pi}}$
  • D. ${{h} \over {4\pi}}$