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HSC 2002 - Physics
Exemplar Sample
Question 31
Marks
Question 31 — From Quanta to Quarks (25 marks)
(a)
(b)
(i)
Describe Davisson and Germer’s experiment that confirmed the
de Broglie hypothesis of wave-particle duality.
2
(ii)
Explain the stability of the electron orbits in the Bohr atom, using
de Broglie’s hypothesis.
4
The diagram shows the kinetic energy distribution of the electrons emitted in the
210
β-decay of 210
83 Bi into 84 Po. The energy released during β-decay depends on the
mass defect in the transmutation, as it does in nuclear fission.
Relative number of electrons
9
Nucleus
or particle
8
7
6
5
4
Mass
(amu)
210Bi
209.938 57
210Po
209.936 78
e
0.000 55
3
2
End-point Ek(max)
1
0
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3
Kinetic energy of electrons, Ek (MeV)
(i)
Identify the scientist who suggested that the existence of the neutrino
relates to the need to account for the energy distribution of electrons
emitted in β-decay.
1
(ii)
Use the data to calculate the mass defect in the β-decay of
(Assume that the neutrino is a massless particle.)
210
83 Bi.
2
(iii)
Account for the energy distribution of electrons emitted in this β-decay.
3
Question 31 continues on page 35
– 34 –
HSC 2002 - Physics
Exemplar Sample
Marks
Question 31 (continued)
(c)
The diagram represents the four spectral lines in the visible region of the
hydrogen spectrum known as the Balmer Series.
Hδ
(d)
Hγ
Hβ
Hα
410 434
486
656
NOT TO
SCALE
Wavelength (nm)
(i)
Explain how the Balmer Series provides strong experimental evidence in
support of Bohr’s model of the hydrogen atom.
3
(ii)
Calculate the wavelength of the next line in the Balmer Series.
3
Discuss how neutron scattering and ONE other process have been used to
increase our understanding of the structure of matter.
End of Question 31
– 35 –
7
HSC 2002 - Physics
Exemplar Sample
Question 31
HSC 2002 - Physics
Exemplar Sample
HSC 2002 - Physics
Exemplar Sample
HSC 2002 - Physics
Exemplar Sample
HSC 2002 - Physics
Exemplar Sample
HSC 2002 - Physics
Exemplar Sample
HSC 2002 - Physics
Exemplar Sample
HSC 2002 - Physics
Exemplar Sample