Applied Physics 2 - May 2015

First Year Engineering (Semester 2)

TOTAL MARKS: 60
TOTAL TIME: 2 HOURS (1) Question 1 is compulsory.
(2) Attempt any three from the remaining questions.
(3) Use suitable data wherever required.
(4) Figures to the right indicate full marks.

Attempt any five of the following:

1 (a) Comment on colours in a soap film in sunlight.(4 marks) 1 (b) What is Rayleigh's criterion of resolution? Define resolving power of a granting.(4 marks) 1 (c) Calculate V number for an optical fiber having numerical aperture 0.25 and core diameter 20 μm if it is operated at 1.55 μm.(4 marks) 1 (d) Compare light from ordinary source with laser light.(4 marks) 1 (e) How phase difference between two signals is measured using CRO?(4 marks) 1 (f) What are the properties of matter waves?(4 marks) 1 (g) A superconductor has a critical temperature 3.7K at zero magnetic field. A 0K the critical magnetic field is 0.0306 Tesla. What is the critical magnetic field at temperature 2.0K?(4 marks) 2 (a) Show that the diameter of Newton's nth dark ring is proportional to square root of ring number. In Newton's rings experiment the diameter of 5^th dark ring was 0.336 cm and that of 15^th dark ring was 0.590 cm. Calculate the radius of curvature of Plano-convex lens if wavelength of light used is 5890 Å.(8 marks) 2 (b) Derive an expression for numerical aperture of step index optical fiber. What are the adavantages of using an optical fiber?(7 marks) 3 (a) Explain construction and working of He-Ne laser. What are its merits?(8 marks) 3 (b) Derive the condition for thin transparent film of constant thickness to appear bright and dark when viewed in reflected light.(7 marks) 4 (a) Calculate the maximum order of diffraction maxima seen from a plane diffraction grating having 5500 lines per cm if light of wavelength 5896 Å falls normally on it.(5 marks) 4 (b) Derive Schrodinger's time-independent wave equation.(5 marks) 4 (c) Define the term superconductivity. Show that in the superconducting state the material is perfectly diamagnetic.(5 marks) 5 (a) A slit of width 0.3 mm is illuminated by a light of wavelength 5890 Å. A lens whose focal length is 40 cm forms a Fraunhofer diffraction pattern. Calculate the distance between first dark and the next bright fringe form the axis.(5 marks) 5 (b) An electron is accelerated through 1000 volts and is reflected from a crystal. The first order reflection occurs when angle is 70°. Calculate the inter planar spacing of a crystal.(5 marks) 5 (c) Explain construction and working of Atomic Force Microscope.(5 marks) 6 (a) State Heisenberg's uncertainty principle. Show that electron cannot pre-exist in free state in a nucleus.(5 marks) 6 (b) Draw a labelled diagram and explain construction and working of CRT.(5 marks) 6 (c) Explain top down and bottom up approaches to prepare nanomaterials.(5 marks)