JUNE-2021
B. Sc. (IV Semester) Examination
PHYSICS
Paper: PHY-241 (Old Course)
Modern Physics (Atomic and Nuclear Physics and Special Theory of Relativity)
Full Marks : 60
Pass Marks : 35%
Time : Two Hours
Note: 1. Students have to attempt Q No. 1 and any other three questions from Section A.
2. Students have to attempt any one question from Section B.
Section - A
(Atomic and Nuclear Physics)
1. Answer the following questions (2x5=10)
(a) What is the main limitation of Rutherford model?
(b) Write properties of positive ray.
(c) How the radius of nuclei depends on mass number?
(d) What is a positron?
(e) Why it became difficult to detect neutrino?
2. Describe Millikan oil drop experiment to determine charge of electron. 10
3. What conclusions can be drawn from –
(a) Binding energy graph. Why energy released in fusion in much higher than the fission reaction. 5
(b) Derive radioactive disintegration equation. 5
4. (a) Mention different types of Beta Decay and explain their mechanism. 5
(b) Describe the principle, construction and working of nuclear reactor. 5
5. Write short note on any two - (5x2=10)
(a) Bain bridge mass spectrograph
(b) Frank-Hertz experiment
(c) Geiger-Nuttal Law
Section – B
(Special Theory of Relativity)
6. Describe Michelson-Morley experiment and explain its significance. 10
7. Derive Lorentz transformation equation and explain time dilatation from this. 10
