1 A radioactive source emits only β- particles.
(a) A scientist wishes to investigate the deflection of β-particles by an electric field. Draw a
labelled diagram to suggest a suitable experimental arrangement.
[3]
(b) State how the apparatus would be used to show the deflection of the β-particles by the
electric field.
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(c) State how the results would show the deflection of the β-particles.
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(d) Explain the direction of the deflection obtained.
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[ Total : 7 ]
PhysicsAndMathsTutor.com
2 (a) The decay of a nucleus of radium 226 88
Ra leads to the emission of an α-particle and
leaves behind a nucleus of radon (Rn).
In the space below, write an equation to show this decay. [2]
(b) In an experiment to find the range of α-particles in air, the apparatus in Fig. 11.1 was
used.
α−particle source detector
ruler
Fig. 11.1
The results of this experiment are shown below.
count rate / (counts/minute) 681 562 441 382 317 20 19 21 19
distance from source to detector/cm 1 2 3 4 5 6 7 8 9
(i) State what causes the count rate 9 cm from the source.
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(ii) Estimate the count rate that is due to the source at a distance of 2 cm.
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(iii) Suggest a value for the maximum distance that α-particles can travel from the
source.
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(iv) Justify your answer to (iii).
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[4]
PhysicsAndMathsTutor.com [Total : 6 ]
3 (a) A radioactive isotope emits only α-particles.
(i) In the space below, draw a labelled diagram of the apparatus you would use to
prove that no β-particles or γ-radiation are emitted from the isotope.
(ii) Describe the test you would carry out.
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(iii) Explain how your results would show that only α-particles are emitted.
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[6]
PhysicsAndMathsTutor.com
(b) Fig. 11.1 shows a stream of α-particles about to enter the space between the poles of a
very strong magnet.
α-particles
S
Fig. 11.1
Describe the path of the α-particles in the space between the magnetic poles.
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[Total : 9]
PhysicsAndMathsTutor.com
4 (a) A sodium nucleus decays by the emission of a -particle to form magnesium.
(i) Complete the decay equation below.
24 Na
11 → Mg +
(ii) Fig. 11.1 shows -particles from sodium nuclei moving into the space between the
poles of a magnet.
-particles
Fig. 11.1
Describe the path of the -particles between the magnetic poles.
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[5]
PhysicsAndMathsTutor.com
(b) Very small quantities of a radioactive isotope are used to check the circulation of blood
by injecting the isotope into the bloodstream.
(i) Describe how the results are obtained.
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(ii) Explain why a -emitting isotope is used for this purpose rather than one that
emits either -particles or -particles.
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[4]
[Total : 9]
PhysicsAndMathsTutor.com
5 Fig. 10.1 is part of the decay curve for a sample of a β-emitting isotope.
100
% activity
75
50
25
0
0 5 10 15 20
time / days
Fig. 10.1
(a) Use Fig. 10.1 to find the half-life of the isotope.
half-life = .......................... [1]
(b) Complete Fig. 10.1 as far as time = 20 days, by working out the values of a number of
points and plotting them. Show your working. [2]
(c) The decay product of the β-emitting isotope is not radioactive.
Explain why the sample of the radioactive isotope will be safer after 20 days than after
1 day. Support your answer by reference to the graph.
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(d) The isotope used for this decay curve may be represented by the symbol AZX.
Write down an equation, by filling in the gaps below, to show the β-decay of this isotope
to a decay product that has the symbol Y.
AX
Z → + Y [2]
[Total : 6]
PhysicsAndMathsTutor.com
