µ IB | Nuclear Physics

10 quick questions

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10 minutes maximum! (can you do it in 5?)

 

 

1. 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

2. The calculation in question 1 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.

3+4. 23.5 grams of the radioisotope uranium 235 has a total activity (A) of approximately 106 Bq.

3. How many atoms N of uranium 235 are in this sample? (Avogadro's number NA = 6.0 x 1023).

  • A. 23.5 x 1023
  • B. 1.0 x 1022
  • C. 6.0 x 1022
  • D. 6.0 x 1024

4. Which of the following formula can be used to find the decay constant for uranium 235?

5. Which of the following provided evidence for the existence of quantised energy levels within the nucleus?

  • A. Discrete energies of alpha particles.
  • B. Discrete energies of beta particles.
  • C. The discovery of neutrinos.
  • D. The discovery of positrons.

6. A radioisotope sample consisting of 1010 particles has a decay constant of λ=0.5 sec-1. After 2 seconds, the activity will be:

  • A.
1010  
e  
  • B.
5x109  
e  
  • C.
1010 e  
  • D.
5x109 e

 

7-9. These questions are about Rutherford scattering as observed in Geiger and Marsden's experiment.  

7. 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

8. Rutherford predicted that 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

9. 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.
 
10. High energy electrons are directed at lead atoms. The electrons are diffracted around the lead nuclei and an interference pattern is observed, due to the wave-like nature of the electrons. The wavelength of these electrons is called the..
  • A. Rutherford wavelength.
  • B. Planck wavelength.
  • C. Bohr wavelength.
  • D. de Broglie wavelength.