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LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

M.Sc. DEGREE EXAMINATION – CHEMISTRY

GH 37

SECOND SEMESTER – APRIL 2008

CH 2952 – NUCLEAR AND RADIO CHEMISTRY

 

 

 

Date : 29-04-08                  Dept. No.                                        Max. : 100 Marks

Time : 1:00 – 4:00

 

Part A

Answer the following:                                                                     10 x 2 = 20 marks

1. What are magic numbers? What is its significance?
2. What is the difference between sub-atomic particles and basic particles?
3. Why are electrons not found in the nucleus?
4. Why is γ- rays emitted in all nuclear processes?
5. When does emission of X-rays occur from nucleus?
6. What are primary radiolytic products? How are they significant?
7. Explain Szillard Charmer’s process. What is its application?
8. What are stellar reactions?
9. What are synthetic elements?
10. What are thermal neutrons?

Part B

 Answer any EIGHT of the following:                                           8 x 5 = 40 marks

11. What are mesons? How do they stabilize the nucleus?
12. Calculate density of ²⁰Ne nucleus. What is inferred from the value of the density?
13. Account for the following:

(a) Halogens have isotopes with alternate mass numbers. (b) Helium, oxygen and calcium have very few isotopes.

14. Explain decay constant and half-life of a nucleus. Calculate these factors for a process, in which 30% completion was observed in 45 min.
15. What are the limitations of shell model?
16. Explain β⁺ emission and electron capture. How are they related to each other?
17. Explain principle of scintillation counters and their classification
18. Explain energy tapping by nuclear fusion? Why is this process useful for destructive purposes only?
19. What is meant by carbon dating? What are its applications?
20. Explain the working principle of charged particle accelerators.
21. Why is nuclear pollution of hydrosphere considered most dangerous?
22. What is neutron diffraction? What are its advantages and disadvantages?

 

Part C

 Answer any FOUR of the following:                                                4 x 10 = 40 marks

 

23. Discuss the concept of mass defect and binding energy. How is the factor ‘binding energy per nucleon’ useful to predict the stabilities of a nucleii?
24. How does liquid drop model explain various spontaneous processes of an unstable nucleus?
25. Discuss the mechanism of radiolysis of water.
26. Explain the plot of signal size to applied potential obtained in an ion chamber. Also mention the suitable counters in each region.
27. Write an essay on breeder reactors with special reference to working principle and
28. How are solvated electrons produced? Discuss models available for their stabilities.

 

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    LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

M.Sc. DEGREE EXAMINATION – CHEMISTRY

WD 36

SECOND SEMESTER – April 2009

CH 2954 / 2952 – NUCLEAR AND RADIO CHEMISTRY

 

 

 

Date & Time: 27/04/2009 / 1:00 – 4:00       Dept. No.                                                       Max. : 100 Marks

 

 

PART A

Answer the following:                                                                     10 x 2 = 20 marks

 

1. How are basic particles different from sub-atomic particles?
2. Why do nuclei show quadrupole moment?
3. Explain nuclear isomerism?
4. When does a nucleus emit α-particle?
5. What is a compound nucleus? Cite an example.
6. What is the source of neutrons in a fission reactor?
7. What is the range of α particles less than that of β?
8. What is meant by ‘Linear Energy Transfer’?
9. What is the application of positron-annihilation technique
10. What is the principle of carbon-dating?

PART B

 Answer any EIGHT of the following:                                           8 x 5 = 40 marks

 

11. Compare properties of mesons and electrons.
12. Explain any two reasons to expect nucleons inside the nucleii are independent of each other.
13. Using Shell Model of nucleus explain magic numbers.
14. Explain the principle of Mossbauer spectroscopy.
15. A radioactive isotope (mass number=200) emits one α particle with a half life of 30min. If 20g of this isotope was allowed to stand in a sealed vessel for 40min, what shall be the volume (at STP) of helium present in the container?
16. Give an account of counters employed to measure intensity of radiation.

 

 

 

 

 

17. Explain nuclear fusion reaction and its applications.
18. Explain principle and working of cyclotron.
19. Write a note on chemical dosimeters.
20. Discuss the preparation and properties of solvated electrons.
21. How are radioactive isotopes useful in understanding chemical reaction mechanisms?
22. What are the advantages, disadvantages and threats of tapping nuclear energy?

 

PART C

 Answer any FOUR of the following:                                                4 x 10 = 40 marks

 

23. Using concepts of liquid drop model derive an expression for binding energy of a nucleus.
24. Discuss various spontaneous and induced nuclear processes.
25. Explain the use of fission reaction to produce energy and principle involved in it.
26. Explain proposed mechanisms for radiolysis of water.
27. Explain the principle and uses of isotope dilution analysis.
28. Write short notes on
    • Szillard Charmer’s Process.
    • Aufbau Order for filling of nucleons in shells.

 

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LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

M.Sc. DEGREE EXAMINATION – CHEMISTRY

SECOND SEMESTER – APRIL 2012

CH 2954 – NUCLEAR AND RADIO CHEMISTRY

 

 

Date : 24-04-2012             Dept. No.                                        Max. : 100 Marks

Time : 9:00 – 12:00

          Part – A

 Answer all the questions:                                                                                                        (10 x 2 = 20)

 

1. What is meant by mass defect of a nucleus?
2. What is binding energy per nucleon? What is its significance?
3. Derive a relationship between t_1/2 and decay constant of a radioactive isotope.
4. What are dosimeters? How are they classified?
5. What is meant by electron capture?
6. When does a nucleus emit gamma ray?
7. What are nuclear isomers?
8. What is n/p ratio of a nucleus? What is its significance?
9. What is meant by compound nucleus?
10. How are nuclear processes classified? Give examples for each class.

 

Part – B

Answer any eight questions:                                                                                                    (8 x 5  = 40)

 

11. Discuss mesons in terms of their types, characteristics and roles.
12. Why are electrons not found in the nucleus?
13. Explain odd-even rule with examples.
14. An isotope of plutonium with mass number 240 disintegrates to form stable ²³² Assuming only a and b^–particles are emitted, deduce the number of a and b^– emitted in this process.
15. Explain the difference between a spallation reaction and nuclear fission reaction citing an example.
16. Natural isotopic abundance of ⁷⁹Br and ⁸¹Br are 75% and 25% respectively. Calculate the atomic weight of bromine obtained from natural sources ?
17. How are nuclear wastes disposed?
18. What are the qualities of a good coolant used  in nuclear reactors?
19. Account for the fact that tin has many isotopes whereas lead has only a few.
20. What is meant by ‘Hot atom chemistry’? What is its application?
21. Briefly explain an experiment to prove that large volume of an atom is empty space.
22. Explain spontaneous and induced nuclear processes with one examples.

Part – C

Answer any four questions:                                                                                                     (4 x 10 = 40)

 

23. Discuss factors affecting stability of a nucleus.
24. Discuss any two models available for filling of nucleons in the nucleus.
25. Why are nuclear fusion reactions unsuitable for energy tapping?
26. Explain the production of solvated electrons and a method to study its properties.
27. Explain the use of radioactive isotopes in understanding chemical reaction mechanisms.
28. Explain the working and use of Fricke dosimeter.

 

 

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