1. Which of the following, observed during a radioactive-decay experiment, provide evidence for the existence of nuclear energy levels?

I.   The spectrum of alpha particle energies
II.  The spectrum of beta particle energies 
III. The spectrum of gamma ray energies 

 
2. An electron of initial energy E tunnels through a potential barrier. What is the energy of the electron after tunnelling?
 
3. Alpha particles with energy E are directed at nuclei with atomic number Z. Small deviations from the predictions of the Rutherford scattering model are observed.

Which change in E and which change in Z is most likely to result in greater deviations from the Rutherford scattering model?

 
4. A positively charged particle of charge q and mass m is accelerated from rest through a potential V. After acceleration the de Broglie wavelength of the particle is λ. Which of the following is equal to λ?
 
5. A proton and an alpha particle have the same de Broglie wavelength.

Which of the following is approximately the ratio 

 
6. A particle has a de Broglie wavelength λ and kinetic energy E. What is the relationship between λ and E?
 
7. A particle is accelerated from rest through a potential difference V. Which of the following graphs best shows how the de Broglie wavelength λ associated with the particle varies with V?
 
8. Two radioactive nuclides, X and Y, have half-lives of 50 s and 100 s respectively. At time t = 0 samples of X and Y contain the same number of nuclei.

What is  when t = 200 s?

 
9. A photoelectric cell is connected in series with a battery of emf 2 V. Photons of energy 6 eV are incident on the cathode of the photoelectric cell. The work function of the surface of the cathode is 3 eV.

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What is the maximum kinetic energy of the photoelectrons that reach the anode?

 
10. Monochromatic electromagnetic radiation is incident on a metal surface. The kinetic energy of the electrons released from the metal
 
11. Which of the following is evidence for the wave nature of the electron?
 
12. A beam of electrons is accelerated from rest through a potential difference V. The de Broglie wavelength of the electrons is λ. For electrons accelerated through a potential difference of 2V the de Broglie wavelength is
 
13. The following observations are made during nuclear decays.

I. Discrete energy of alpha particles

II. Continuous energy of beta particles

III. Discrete energy of gamma rays

Which of the observations provide evidence of the existence of nuclear energy levels?

 
14. A particle of fixed energy is close to a potential barrier.

Which changes to the width of the barrier and to the height of the barrier will always make the tunnelling probability greater?

 

 
15. What can be used to calculate the probability of finding an electron in a particular region of space?
 
16. The half-life of a radioactive isotope is 10 days. What is the percentage of the sample remaining after 25 days?
 
17. Evidence for nuclear energy levels comes from discrete energies of

I. alpha particles
II. beta particles
III. gamma ray photons.

Which of the above statements is/are true?

 
18. A neutron of mass m is confined within a nucleus of diameter d. Ignoring numerical constants, what is an approximate expression for the kinetic energy of the neutron?
 
19. Which of the following experiments provides evidence for the existence of matter waves?
 
20. Ultra-violet light is shone on a zinc surface and photoelectrons are emitted. The sketch graph shows how the stopping potential

Vs varies with frequency f.

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Planck’s constant may be determined from the charge of an electron e multiplied by

 
21. According to the Heisenberg uncertainty principle the quantity paired with momentum is
 
22. Two samples X and Y of different radioactive isotopes have the same initial activity. Sample X has twice the number of atoms as sample Y. The half-life of X is T. What is the half-life of Y?
 
23. A photon interacts with a nearby nucleus to produce an electron. What is the name of this process?
 
24. In the Schrödinger model of the hydrogen atom, the probability of finding an electron in a small region of space is calculated from the
 
25. Deviations from Rutherford scattering are detected in experiments carried out at high energies. What can be deduced from these deviations?
 
26. An electron is accelerated from rest through a potential difference V.

Which of the following is the de Broglie wavelength of the electron after acceleration?

 
27. According to the Bohr model for hydrogen, visible light is emitted when electrons make transitions from excited states down to the state with n = 2. The dotted line in the following diagram represents the transition from n = 3 to n = 2 in the spectrum of hydrogen.

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Which of the following diagrams could represent the visible light emission spectrum of hydrogen?

 
28. Nuclear density
 
29. A radioactive element has decay constant

λ (expressed in s–1). The number of nuclei of this element at t = 0 is N. What is the expected number of nuclei that will have decayed after 1 s?

 
30. The radii of nuclei may be determined by
 
31. An electron of mass m has an uncertainty in its position r. What is the uncertainty in the speed of this electron?
 
32. Which of the following is an assumption of the Schrödinger model of the hydrogen atom?
 
33. Photoelectrons are emitted at a certain rate when monochromatic light is incident on a metal surface. Light of the same intensity but of higher frequency is now used. After this change, the rate of emission of electrons from the surface is
 
34. When the cathode of a photoelectric cell is illuminated with red light, a photoelectric current is produced in the cell. The illumination is changed to blue light but the rate at which photons arrive at the cathode remains the same. Which of the following statements is/are correct under these conditions?

I. The number of electrons released is unchanged
II. The current falls to zero
III. The kinetic energy of the electron increases

 
35. In the photoelectric effect, the following observations may be made.

I.     The kinetic energy of the emitted electrons increases with increasing light frequency.

II.     The electrons are emitted without time delay.

Which of these observations, if any, can be explained in terms of the wave theory of light?

 
36. Light that is shone onto a metal surface may result in the emission of electrons from the surface. Three statements regarding the emission of the electrons are the

I. number of electrons emitted per unit time depends on the intensity of the incident light
II. energy of the electrons depends on the frequency of the incident light
III. emission of the electrons takes place instantaneously.

Which of the above statements can only be explained by assuming light consists of photons?

 
37. When monochromatic light is incident on a metallic surface, electrons are emitted from the surface. The following changes are considered.

I.    Increase the intensity of the incident light
II.   Increase the frequency of light
III.  Decrease the work function of the surface

Which changes will result in electrons of greater energy being emitted from the surface?

 
38. The diameter of a silver-108

 nucleus is approximately three times that of the diameter of a nucleus of

 
39. The square of the amplitude of the electron wave function in an hydrogen atom is a measure of the
 
40. An electron accelerated from rest through a potential difference V has de Broglie wavelength λ. What is the wavelength of an electron accelerated from rest through a potential difference of 2V?
 
41. The responses showed that the majority of the candidates understood that the wavelength gets smaller with increasing speed of the electron (responses B and D). However they failed to realize that the energy given to the particle is proportional to the square of the velocity. Hence the factor of √2 is necessary when considering the momentum.
 
42. If there is no uncertainty in the value of the de Broglie wavelength of a particle then this means that
 
43. When electromagnetic radiation falls on a photocell, electrons of mass

me are emitted, provided the frequency of the radiation is greater than f0. What is the maximum speed of the electron when radiation of frequency f falls on the photocell?

 
44. Three phenomena associated with nuclear and quantum physics are

I. Einstein photoelectric effect
II. de Broglie hypothesis
III. Rutherford alpha particle scattering.

Which of the phenomena can be verified by firing electrons at a metal surface?

 
45. Which of the following is a correct statement associated with the photoelectric effect?