10 minutes maximum! Can you do it in 5?

Constructive and destructive interference patterns can be produced with..

  • A. only photons.
  • B. only photons and electrons.
  • C. only electrons and protons.
  • D. photons, electrons and protons.

2. The formula E= hf can be used with..

  • A. only photons.
  • B. only photons and electrons.
  • C. only electrons and protons.
  • D. photons, electrons and protons.

3.The energy levels of electrons in a hydrogen atom can be calculated using the Bohr model.

Which of the following formulas can be used to calculate the energy released (as a photon) when an electron drops from n=2 to n=1?

  

4. For an electron orbiting the hydrogen nucleus, what is the quantity mvr equal to ?

  • A. The centripetal force required to maintain a circular orbit.
  • B. The angular momentum of the electron.
  • C. The energy of the electron.
  • D. The linear momentum of the electron at any point.

5.A high energy photon can instantaneously produce matter from energy through the process of pair production. An example of this is:

  • A. A photon producing a neutron and a proton.
  • B. A photon producing two neutrons.
  • C. A photon producing a proton and an electron.
  • D. A photon producing an electron and a positron.

6. For an electron to be trapped in the nucleus of an atom, its position must be known to an accuracy of about 10-15 m. This means the uncertainty in the momentum must be of the order of

  • A. 10-15 kg ms-1
  • B. 10-17 kg ms-1
  • C. 10-19 kg ms-1
  • D. 10-21 kg ms-1

7-10. An electron has kinetic energy Ee. It is trapped by two potential barriers of energy Eb as shown in this diagram.
Eb > Ee, so using classical physics, the electron cannot escape. However the electron still has a small chance of appearing on the other side of these barriers.

 

7. What is the name of this effect?

  • A. Quantum tunnelling.
  • B. Barrier jumping.
  • C. Wave function tunnelling.
  • D. Probability tunnelling.

8. How do the following changes affect the probability of the electron appearing on the other side of the barrier?

  
Increase the width W Increase the quantity (Eb-Ee)
A
 no effect no effect
B
 lower probability no effect
C
 no effect lower probability
D
 lower probability lower probability

9. Which of these is proportional to the probability of finding the electron at a particular location?

  • A. The wave function
  • B. The square of the wave function
  • C. The angular momentum
  • D. The square of the angular momentum

10. Which of these statements about the value of the wave function is correct?

 Within the barrier Outside the barrier
A
 zero at all points zero at all points
B
 non-zero zero at all points
C
 zero at all points non-zero
D
 non-zero non-zero