1. Electrons orbit the nucleus at specific energy levels, or shells. An electron falling from a high energy level to a lower level will have

  • A. absorbed a photon
  • B. emitted a photon
  • C. absorbed a neutrino
  • D. emitted a neutrino
2. The diagram shows electron energy levels within a hydrogen atom. hydrogen energy levels simple diagram

Of the 4 possible transitions listed below, which transition will give rise to an emission spectral line of the shortest wavelength?

  • A. from n=1 to n=2
  • B. from n=2 to n=3
  • C. from n=3 to n=2
  • D. from n=2 to n=1

3. Which of these word equations summarises beta decay ( β - ) ?

  • A. neutron → proton + beta particle + neutrino
  • B. proton → neutron + beta particle + neutrino
  • C. neutron → proton + beta particle + antineutrino
  • D. proton → neutron + beta particle + antineutrino

 

4. When Uranium decays it emits an alpha particle, forming an isotope of Thorium. Which of the following decay equations is correct?

A.
238
 U →
232
 Th
+
2
 α
92
90
2
B.
238
 U →
236
 Th
+
2
 α
92
90
2
C.
238
 U →
234
 Th
+
4
 α
92
90
2
D.
238
 U →
232
 Th
+
4
 α
92
90
2

5. Nuclides and isotopes have different definitions but are often confused. The correct definitions are:

  Nuclides Isotopes
A Different proton AND neutron numbers Same number of protons, different number of neutrons
B Different proton AND neutron numbers Same number of neutrons, different number of protons
C Different proton OR neutron numbers Same number of protons, different number of neutrons
D Different proton OR neutron numbers Same number of neutrons, different number of protons

6+7. The graphs below show how the activity of a sample varies over time.

6. Which has the correct decay characteristics for a radioactive sample?

radioactive decay curves x 4

7. Using the correct graph above, what is the half-life of this isotope?

  • A. 2 days
  • B. 4 days
  • C. 6 days
  • D. 8 days
8. A sample of 64g of radioisotope has a half life of 6 hours. After 2 days the mass of original isotope remaining is:
  • A. 8 g
  • B. 0.5 g
  • C. 0.25 g
  • D. 0.125 g

9. Two radioisotopes emit gamma rays of different frequencies. The gamma ray from isotope X has f=1020 Hz and from Y, f=1021 Hz.

Which of these correctly decribes the gamma rays emitted?

  Gamma ray with shortest wavelength Gamma ray with highest energy
A. X X
B. X Y
C. Y X
D. Y Y

10. Binding energy per nucleon is usually stated as a positive value. When helium nuclei fuse together to form beryllium nuclei in the centre of a star, how does the binding energy and the mass defect change?

  • A. the binding energy per nucleon inceases and the mass defect increases
  • B. the binding energy per nucleon deceases and the mass defect increases
  • C. the binding energy per nucleon inceases and the mass defect decreases
  • D. the binding energy per nucleon deceases and the mass defect decreases