Tiêu đề Physics QB 2024.pdf ✅

8 (a) A parallel beam of sodium light of wavelength 5890 A0 is allowed to be incident normally on a plane transmission grating and second order spectral lines are found to be deviated through 300. Calculate the number of lines on the grating. b) A soap film 5x10 -5cm thick is viewed at an angle of 350to the normal. Find the wavelength of light in the visible spectrum which will be absent in the reflected light. (μ =1.33) 4 4 9 a) How many orders will be visible if the wavelength of the incident radiation is 5000A0 and the number of lines on the grating is 2620 in one inch. b) Explain diffraction at single slit and hence derive the expression for the condition of maxima and minima.. 4 4 10 a) Explain the formation of Newton’s rings in reflected light and show that the radii of dark rings are proportional to the square root of natural numbers. April -May 24 b) Two coherent sources whose intensity ratio is 81:1 produce interference fringes. Deduce the ratio of maximum intensity to minimum intensity. 6 2 Unit-2: Laser and Optical fiber Q.No. Questions Mar ks 11 What are laser characteristics? Describe principle and working of He-Ne Laser. Why is a long narrow discharge tube used in He-Ne laser and what is the role of He here. How does laser differ from ordinary light. Nov Dec 22, Nov Dec 21 8 12 Explain construction and working of Ruby Laser and discuss its drawbacks. Write any two applications. Nov Dec 23 8 13 Explain with neat diagram absorption, spontaneous emission and stimulated emission of radiation. What is the reason for the monochromaticity of laser beams? Derive the relation between Einsteins coefficients. Nov Dec 21 8

21 (a)What is a matter wave .Derive the expression for it and discuss the significance of change in mass and velocity on it. (b) Describe Davisson and Germer Experiment. What does it confirm? 4 4 22 Derive time independent Schrodinger wave equation. 8 23 Derive time dependent Schrodinger wave equation. April May -24 Nov Dec 22, Nov Dec 21 8 24 State and prove Heisenberg’s uncertainty principle. Explain its consequence with examples. . Nov Dec 22 8 25 Derive one dimensional Schrodinger wave equation for a particle in a box and hence find energy eigenvalue for it. 8 26 (a) Explain with the help of uncertainty principle why electron cannot reside inside the nucleus. (b) Calculate the uncertainty in measurement of momentum of an electron if the uncertainty in its location is 1Å. April May -22 4 4 27 (a) What is a wave packet? Explain Born interpretation. April May -24 Nov Dec 22 April May -22 (b) Calculate the energy required for an electron to jump from ground state to the second excited state in a potential well of width L. 4 4 28 Derive expression for energy eigen value and normalized eigen function for a particle trapped in one dimensional infinite potential well of width a. April May -24 , April May -22 , Nov Dec 22 8 29 (a) Explain de Broglie hypothesis of matter wave .Compute the wavelength of electron moving with a speed of 2x 107 m/s. Nov Dec 23 (b) A certain Photon has a momentum of 1.5 x 10-27 kg m/sec What will be the photons de- Broglie wavelength. 4 4 30 (a)Uncertainty in position of particle of 25 gm in space is 10-5 m Calculate the uncertainty in velocity . Nov Dec 23 (b) Find the energy of an electron moving in one dimension in an infinite high potential box of width 1.5 A0 4 4