B.Sc. DEGREE EXAMINATION –PHYSICS
SUPPLEMENTARY EXAMINATION – JUNE 2007
PH 5500 - ATOMIC & NUCLEAR PHYSICS
Date & Time: 26/06/2007 / 9:00 - 12:00 Dept. No. Max. : 100 Marks
PART – A
Answer ALL questions.
1. What is Stark effect?
2. Describe the coupling schemes in an atom.
3. Describe how a photo-voltaic cell functions.
4. What is the importance of Moseley’s law regarding X-rays?
(10 x 2 = 20 Marks)
5. Explain mass defect and packing fraction in an atom.
6. State Lawson’s criterion for nuclear fusion.
7. What are the breeder reactors? Indicate any two disadvantages of nuclear power plant.
8. Differentiate Baryon, Meson and Lepton.
9. What are Magic numbers?
10. State Geiger-Nuttall law.
PART – B
Answer any FOUR questions. (4 x 7.5 = 30 Marks)
11. Describe Frank-Herz experiment for determining the critical potentials.
12. a. State any four properties of X-rays. (4+3.5) b. Find the minimum wavelength of X-rays produced by an X-ray tube operated upon 1000 kV. Given h = 6.625x10
-34
Js; e = 1.602x10
-19
C and c = 2.998x10 ms
-1
.
13. What is photoelectric effect? Describe the experimental investigation on the photoelectric effect. (2+5.5)
14.
Explain Yukawa’s Meson Theory of nuclear forces and show that the mass of meson is approximately 275 times the mass of electron.
15. Explain the terms: Nuclear size, Nuclear mass, and Nuclear density.
PART – C
Answer any FOUR questions. (4 x 12.5 = 50 Marks)
16. a. Describe, with neat diagram, Thomson’s Parabola Method to determine the charge to mass ratio of positive ions. (10) b. In a positive ray apparatus, singly and doubly ionized particles form identical parabolas when the electrostatic fields are respectively 80 and 100 volts per metre.
Compare the masses of the particles, assuming the magnetic field to be same.(2.5)
17. a. What is Compton effect? Give the theory of Compton effect and explain its experimental verification.
b. X-rays of wavelength 0.7080 Å are scattered from a carbon block through an angle of 90 o
and are analysed with a calcite crystal, the interplanar distance of whose reflecting planes is 3.13 Å. Determine the angular separation, in the first order, between the modified and the unmodified rays.
(8+4.5)
18. Derive Four-Factor formula.
19. Explain Liquid Drop Model for the nucleus and hence derive Weizacker semi empirical binding energy formulae for a nucleus.
20.
Explain Gamow’s theory of Alpha decay. And how is it experimentally verified?
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