PSPM BY CHAPTER

(ii) Why is the resolving power of an electron microscope higher than an optical
microscope?
[3 marks]

ANSWERS:
TOPIC 10: WAVE PROPERTIES OF PARTICLE

1. 4.64×10-11 m
4. (c) (i) /2 (ii) /2
5. (b) (i) 3.315×10-23 kg m s-1 (ii) 3.64×107 m s-1
6. (a) (ii) 7.0896×10-13 m, 9.35×10-22 kg m s-1, 4.8×10-13 J or 3×106 eV

TOPIC 11: NUCLEAR AND PARTICLE PHYSICS

SESSION 2005/2006 SF027/2 No. 14 (a) (i) & (ii) [1 mark]
1. (a) Define mass defect. [1 mark]

(b) State the relationship between binding energy and mass defect.

SESSION 2006/07 SF027/2 No. 14 (c) & (d)
2. (a) Explain

(i) the mass defect.
(ii) the binding energy.

[2 marks]

(b) Calculate the binding energy per nucleon in MeV for if the mass defect is 1.2 ×
10−28 kg.
[3 marks]

SESSION 2008/09 SF027/2 No. 8 (b)
3. (a) State the meaning of a high binding energy per nucleon to a nuclide.

[1 mark]

SESSION 2008/09 SF027/2 No. 14 (b)
4. (a) (i) *Which of the following elements are isotopes? Justify your answer.

SESSION 2009/10 SF027/2 No. 8

5. (a) Without stating any equation, define binding energy of a nucleus.

(b) Calculate the binding energy of tritium, 3 H in MeV.
1

Mass of tritium = 3.016049 u

Mass of hydrogen = 1.007825 u

[4 marks]

50

SESSION 2011/2012 SF026/2 No. 8 (a)
6. (a) Define nuclear binding energy.

(b) Given the mass of a 151B nucleus is 11.008757 u, calculate the binding energy per
nucleon.
[5 marks]

SESSION 2012/2013 DF045 No. 7 (a) & (b)
7. (a) Define

(i) mass defect.
(ii) binding energy.

(b) Uranium isotope 238 U has atomic mass 238.050783 u. Calculate [2 marks]
92 [9 marks]

(i) the number of proton, neutron and nucleon in the nucleus.

(ii) the mass defect in atomic mass unit, u.

(iii) the binding energy in MeV.

(iv) the binding energy per nucleon.

SESSION 2013/2014 DF045/2 No. 7 (a)
8. (a) (i) Define nucleon number.

(ii) Sketch a graph of binding energy per nucleon against nucleon number. Label
on the graph the region of stable nuclei and the region of fissionable nuclei.
Explain your choice of each region.
[5 marks]

SESSION 2014/2015 DF045/2 No. 7 (a) & (b) [4 marks]
9. (a) Define [6 marks]

(i) mass defect.
(ii) binding energy per nucleon.

(b) The mass of 1263o is 23.01569 u. Calculate the

(i) mass defect in atomic mass unit, u.
(ii) binding energy per nucleon in MeV.

ANSWERS:
TOPIC 11: NUCLEAR AND PARTICLE PHYSICS

2. (b) 5.63 MeV per nucleon
5. (b) 8.48 MeV
6. (b) 6.974 MeV per nucleon
7. (b) (i) 92, 146, 238 (ii) 1.934482 u (iii) 1801.71 MeV (iv) 7.57 MeV/nucleon

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TOPIC 11: NUCLEAR AND PARTICLE PHYSICS

SESSION 2005/2006 SF027/2 No. 8

1. (a) Define the half-life of a radioactive element.

[1 mark]

(b) Carbon dating on a human remains shows the activity of carbon-14 is 0.068 Bq per

gram of carbon. The initial activity of carbon-14 is 0.231 Bq per gram of carbon and

the half-life is 5730 years. Calculate the age of the remains.

[3 marks]

SESSION 2005/2006 SF027/2 No. 14 (b)

2. Isotope 210 Po of mass 1.2 g is used in a battery as its power source. It has a half-life of 140
84

days and emits -particles, each of which has energy 5.3 MeV. After 100 days, calculate

(a) the remaining mass.

[3 marks]

(b) the total energies of -particles.

[3 marks]

(c) the average power produced.

[8 marks]

SESSION 2006/2007 SF027/2 No. 14 (a) & (b)
3. (a) Define

(i) decay constant.
(ii) half life.

[2 marks]
(b) The activity of a radioisotope is 6 × 1010Bq. If 25% of the radioisotope decays in 5

days, calculate

(i) the decay constant.
(ii) the half life of the radioisotope.
(iii) the initial number of the nuclei.
(iv) the time taken for the radioisotope to reduce to 1012 nuclei.

[8 marks]

SESSION 2007/2008 SF027/2 No. 8 (b)
4. (a) How are radioisotope used as tracers in the medicine?

[2 marks]

SESSION 2007/2008 SF027/2 No. 14 (d)

5. (a) FIGURE 28.1 shows the decay curve of a radioactive sample.

(i) Determine the decay constant.

(ii) Write an equation representing the decay curve in FIGURE 28.1.

(iii) Calculate the initial number of the nuclei in the sample.

[5 marks]

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FIGURE 28.1

SESSION 2008/2009 SF027 No. 14 (a)
6. The 13H nuclei decay equation is given by

13H  23He  X  v
where Error! Reference source not found. is an anti-neutrino.
(i) What is X?
(ii) What is the nucleon transformation that occurs during the decay process?
(iii) Write an equation representing the disintegration of nuclei over time.
(iv) Calculate the mass of Error! Reference source not found. that has an activity of 500

GBq if the half-life is 18 years.
[7 marks]

SESSION 2009/2010 SF027 No. 14 (b) & (d)
7. (a) What is an alpha decay?

[2 marks]
(b) Iodine isotope with half-life 8 days and mass number 131 is used in a thyroid

diagnosis. If a patient ingested 600 µg of the isotope, calculate the activity of the
isotope immediately after ingestion.

[7 marks]

SESSION 2010/2011 SF027 No. 14 (c) & (d)
8. (a) The number of radioactive decay per second, dN and the number of remaining

dt
nuclei, N is given by the decay law.
(i) Derive the decay law.
(ii) Sketch a graph of N against t on the same axis for different values of λ1 and λ2

where λ2  λ1.
[5 marks]

(b) A radioisotope has an initial activity 9 mCi. After 16 hours, its activity reduces to 7
mCi. Calculate
(i) the half-life of the isotope.
(ii) the initial number of nuclei.
[4 marks]

53

SESSION 2011/2012 SF026/2 No. 8 (b), (c) & (d)

9. (a) Show that the radioactive decay equation can be written as

1

N  N0  1 T
 2 

where No is the initial number of nuclei, N is the number of remaining nuclei, t is the
decay time, and T is the half-life.

[3 marks]

(b) A sample of 28131Bi contains 2.00 x 109 nuclei. Given the half-life of 28131Bi is
2.14 minutes, calculate

(i) the initial activity in decays per second.

(ii) the number of the nuclei remaining after 42.8 s.

[5 marks]

(c) An energy of 208 MeV is released when a U235 nucleus undergoes fission. Calculate

92

the amount of U235 in gram needed to release 4.40 x 1017 J of energy.

92

[2 marks]

SESSION 2012/2013 SF026/2 No. 8
10. (a) (i) State the properties of particles emitted during radioactive decay.

(ii) State the risk arises from radioactive particles.
[2 marks]

(b) The activity of a sample of radon-222 is 200 Bq. The half-life of radon is 3.8 days.
(i) Calculate the decay constant of radon-222.
(ii) Calculate the number of radon-222 atoms in the sample.
(iii) How long does it take for the activity to decrease to 60 Bq?
[6 marks]

SESSION 2012/2013 DF045 No. 8
11. (a) (i) State two properties of an alpha particle.

(ii) State decay law.
[3 marks]

(b) The half-life of a radioactive 215At is 100 s. For a sample that contains 5 mg of the
element,

(i) Calculate the initial activity and the activity after 300 s.
(ii) Sketch an activity-time curve for the decay.

(c) Explain briefly two applications of radioisotopes as tracers. [8 marks]
[4 marks]

SESSION 2013/2014 DF045/2 No. 8

12. (a) Explain
(i) α decay.
(ii) β− decay

[2 marks]

(b) The activity of a sample of radioisotope changes from 1500 Bq to 1300 Bq in 25
minutes. Calculate the

54

(i) decay constant.
(ii) half-life.
(iii) initial number of radioactive nuclei.
(iv) number of radioactive nuclei decayed within the 25 minutes.

[13 marks]

SESSION 2014/2015 DF045/2 No. 8

13. (a) What is meant by
(i) α-decay?

(ii) β+-decay?

(iii) decay constant?

(b) (i) Derive the expression, N = No e-λt from the decay law. [3 marks]

(ii) Explain the application of radioisotopes as tracers.

[5 marks]

(c) A sample of radioisotopes thorium-234 with a half-life of 24.5 days has an activity

6.1x 1014 decays per second. Calculate

(i) the decay constant.

(ii) the mass of the sample

[7 marks]

ANSWERS:
TOPIC 11: NUCLEAR AND PARTICLE PHYSICS

1. (b) 10109 years
2. (a) 0.73 g (b) 1.14×10 9 J (c) 132 W

3. (b) (i) 6.66×10-7 s-1 (ii) 1.04×106 s (iii) 9.01×106 nuclei (iv) 1.71×107 s
5. (a) (i) 4.62×10-8 s-1 (ii) 8×1012 e-4.62×10-8t (iii) 1.73×1020 nuclei
6. (iv) 2.04×10-3 g

7. (b) 2.38×1017 decays per day OR 2.77×1023 decays per second
8. (b) (i) 44.12 hours (ii) 7.6 x 1013 nuclei

9. (b) (i) 1.1×107 decay per second (ii) 1.587×109 nuclei (c) 5.15×106 g
10. (b) (i) 2.11×10-6 s-1 (ii) 9.48×107 nuclei (iii) 6.6 days
11. (b) (i) 9.7×1022 Bq, 1.5×1028 Bq

55