BSc Physics SEM I 2017 18 2017-18 ATKT PHYSICS Paper II Question Paper - Mumbai University | munotes

Questions asked in this paper

1. Q2 Use of non- programmable calculator is allowed
2. Q4 Symbols have their usual meanings unless mentioned
3. Q1 (A) Select the correct option 12 marks
   • i) If half life of Au is 2.7days. Then its decay constant is
   • (a) 2.73x (b) (c) None of these
   • ii) As the number of nucleons in nuclei goes on increasing, the binding energy
   • (a) first increases and then decreases (b) remains constant
   • iii) Radio isotopes have:
   • (a) same mass number but different atomic number
   • (b) same atomic number but different mass number
   • (c) same mass number and same atomic number
   • (d) same density but different atomic number
   • iv) The inverse of pair production processes is called
   • (a) Pair annihilation
   • (c) Both (a).and (d) None of these
   • v) The values of X Y in the reaction 180 + 7H £0 + 3H are:
   • (c) X=15 ,Y=1 None of these As the temperature of blackbody raised the maximum intensity of radiation emitted is displaced towards the.side
   • (c) frequency (d) None of these
   • (B) . Answer sentence : 03
   • i) What is Binding Energy of a nucleus? li) State Bragg’s law
   • iii) What is Nuclear Fission?
   • i) One a.m.u. is equivalent to MeV If Q value of nuclear reaction is negative, the reaction is called
   • iii) Laue pattern is obtained due to of X-rays at lattice
   • iv) For perfectly black body the coefficient of absorption is
   • v) Compton scattering the change in wave length is maximum if angle of
4. Q2 (A) Attempt any one 8 marks
   • i) State law of radioactive disintegration and obtain a relation governing the radioactive decay, Define the terms decay constant, half life and mean life
   • ii) Define packing fraction .Draw the graph showing the variation of packing fraction with the mass number and state the inferences drawn from the graph
   • (B) Attempt any one 08
   • i) State law of successive disintegration and derive the expression for the number of atoms in first two daughter elements
   • ii) Derive an expression to estimate the nuclear radius from Rutherford’s
   • (C) Attempt any one 04
   • i) A charcoal sample from an ancient fire-pit showed a activity of 11.3 counts per gm per min. The absolute activity of in a living tree is around per gm per min. Estimate the age of the charcoal sample. Half life of is 5730 years
   • ii) Estimate the binding energy per nucleon of helium nucleus
5. Q3 (A) Attempt any one 8 marks
   • i) With the help of neat diagram, explain the construction and working of Geiger
   • ii) Derive the equation of the Q-value of the nuclear reaction
   • (B) Attempt any one 08
   • i) Explain the principle, construction and working of a Proportional counter with the help of neat diagram
   • ii) State and explain the conservation laws of nuclear reactions
   • (C) Attempt any one 04
   • i) Determine the Q-value of the nuclear reaction 7N!4 (a,p) sO!”
   • ii) An loses all of its energy in a gas and produces 2.25 x 105 ion-pairs .If energy required to create one ion-pair is 32eV, What is the energy of an a- particle
   • (A). Attempt any one 08 What is Compton effect? Derive an expression for Compton shift in wavelength of the photon
   • ii) Describe Davisson-Germer experiment to verify the dual nature of
   • (B) Attempt any one 08
   • i) Discuss the distribution of energy in the spectrum of black body
   • ii) Describe how X-rays are produced using Coolidge tube
   • (C) Attempt any one 04
   • i) Calculate the wavelength of the matter waves associated with a ball of mass 6.62 x 102kg and moving with a velocity 2m/s. Planck’s
   • ii) Calculate the critical voltage required to stimulate the emission of characteristics lines of K-series tungsten, if K absorption edge is
6. Q5 Attempt any four 20 marks
   • i) Write short note on Carbon dating
   • ii) Discuss in brief the stability of nuclei
   • iii) Find the shortest wavelength of X rays emitted when electrons are accelerated through a potential difference of 35 keV in an X ray tube
   • iv) Describe the construction & principle of working of gas-filled detector
   • v) What do you understand by Gravitational Red shift?
   • vi) State and explain De Broglie hypothesis. State properties of matter

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