IB Nuclear

page 1

 

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

  • 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

 

 

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

  • A. neutronproton + beta particle + neutrino
  • B. protonneutron + beta particle + neutrino
  • C. neutronproton + beta particle + antineutrino
  • D. protonneutron + 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. Which of the following graphs shows how the activity of a sample varies with time?

A. B.
C. D.

 

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. 8g
  • B. 0.5g
  • C. 0.25g
  • D. 0.125g

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