BSc Physics SEM I 2018 19 Dec 2018-19 PHYSICS II Question Paper - Mumbai University | munotes

Questions asked in this paper

• (2) Figures to the right indicate full marks

1. Q2 A) Attempt ANY ONE 8 marks
   • (i) the basis of Rutherford’s alpha scattering experiment, how will you estimate the size of the nucleus? (i1) State the law of successive disintegration of radioactive substance Explain transient equilibrium
   • B) Attempt ANY ONE 8
   • (i) and explain binding of a nucleus. Sketch the graph of binding energy per nucleon against mass number. Explain its
   • (ii) and explain law of radioactive decay. Hence obtain the expression for half-life period
   • C) Attempt ANY ONE 4
   • (i) the distance of closest approach, when alpha particles of energy 5.48 MeV are bombarded on
   • (ii) | In natural carbon the abundance of is 1.3 x and 5730 years is its half-life time. Calculate the number of disintegration/hour in | gram of natural carbon
2. Q3 A) Attempt ANY ONE 8 marks
   • (i) Using the concept of compound nucleus formation, derive an expression for the threshold energy of a nuclear reaction
   • (ii) Explain the construction and working of a GM counter
   • B) Attempt ANY ONE 8
   • (i) Derive an expression for Geiger rule i.e. = CR where is initial velocity of the emitted particle and R is the range of the particle and C is a constant for the particular medium in which the range is defined
   • (ii) Derive an expression for the nuclear disintegration energy balance of mass and energy in a nuclear reaction (Q-value)
   • C) Attempt ANY ONE 4
   • (i) Calculate the Q value for the reaction: Given: The masses of 207.976641 amu,
   • (ii) A neutron beam is incident on a stationary target of The reaction a Q-value of -3.9 MeV. Calculate the lowest neutron energy that will make this reaction possible Assume the masses of nuclei are equal to their mass numbers expressed in Given: 1 amu=931.5 MeV
3. Q4 A) Attempt ANY ONE 8 marks
   • (i) Describe Laue’s experiment on X-ray diffraction
   • (ii) | What is Compton effect? Write the experimental determination of the Compton shift
   • B) Attempt ANY ONE 8
   • (i) Give the elementary proof of Heisenberg’s Uncertainty Principle
   • (ii) | Describe continuous and characteristic X-ray Spectra
   • C) Attempt ANY ONE 4
   • (i) A bullet of mass 20 gm is moving with a speed of 350 m/s, measured with accuracy of 0.05%. Calculate the uncertainty in the location of the bullet
   • (ii) tube emits X-rays with minimum wavelength 0.1 What is the operating voltage of the tube?
4. Q5 Attempt ANY FOUR 20 marks
   • (i) The number of first daughter element is given by; = — Estimate the time (tm) taken by second daughter to attend maximum
   • (ii) Write a short note on nuclear charge and nuclear density
   • (iii) Find the Q-value for the following reaction The masses of the nuclei are given as mass of nitrogen = 14.00753 amu, mass of oxygen = 17.0045 amu, mass of alpha particle = 4.00387 amu and mass of proton is 1.00814 amu
   • (iv). Write short note on nuclear fission and nuclear fusion Derive Bragg’s equation for crystals
   • (vi). In Compton scattering experiment, X-rays are scattered at angle with respect to the incident beam. If the wavelength of scattered X-ray is 3.022 calculate the wavelength of incident

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