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Monday, 3 October 2016

Physical and Geometrical optics- model question paper for BSc. Optometry



1(a) Write a short note on dual nature of light. (04 Marks)
(b) what are wavefronts? Mention two examples. (04 Marks)
(c) Deduce an expression for the total energy of a simple harmonic motion. (08 Marks)
(d) A particle performs harmonic oscillations with a period of 2 seconds. The amplitude of the oscillations is 10 cm. Find the displacement, velocity and acceleration of the particle in 0.2 second after it passes through its equilibrium position, if the beginning of the oscillation coincides with the equilibrium position. (04 Marks)
2(a) What is reflection phase shift? Explain. (04 Marks)
(b) Explain the method of determination of wavelength of a light source using Lloyd’s mirror. (08 Marks)
(c) Write a note on interference in thin films. (04 Marks)
(d) Green light of wavelength 5100 Å from a narrow slit is incident on a double slit. If the overall separation of 10 fringes on a screen 2m away is 2 cm, find the slit separation. (04 marks)
3(a) Write expressions for resolving power and dispersive power of a grating. (04 Marks)
(b) Explain Fresnel’s diffraction at a circular aperture. (06 Marks)
(c) Explain how a grating is used to determine wavelength of light. (06 Marks)
(d) For second order diffraction in a grating, angle of diffraction was 20 degrees. If the wavelength of the light used is 560 nm, determine the grating element. (04 marks)
4(a) Explain the method of construction of a Nicol prism. (06 Marks)
(b) Explain Brewster’s law and Malus law. (04 Marks)
(c) What is optical activity? Explain the working of half shade polarimeter. (06 Marks)
(d) What are quarter wave and half wave plates? (04 Marks)
5(a) Write a short note on Lummer-Brodhun photometer. (04 Marks)
(b) Distinguish between rayleigh scattering and Raman scattering. (04 Marks)
(c) With a neat energy level diagram, explain the working of Ruby laser. (08 Marks)
(d) What is the wavelength of a semiconductor laser, if the material used for the fabrication has a bandgap of 1.486 eV. (04 Marks)
6(a) Write a short note on Fourier transforms spectroscopy. (06 Marks)
(b) What is attenuation in an optical fiber? (04 Marks)
(c) Write a note on avalanche photodiode. (04 Marks)
(d) Determine numerical aperture and acceptance angle of a fiber with core refractive index 1.52 and cladding refractive index 1.50 when placed in (a) air and (b) in water of refractive index 1.33. (06 Marks)
7(a) Explain Fermat’s principle. (06 Marks)
(b) Distinguish between ophthalmatic prisms and reflecting prisms.(06 Marks)
(c) Write a note on chromatic aberration. (05 Marks)
(d) Determine critical angle for total internal reflection if the refractive index of the medium is 1.5. (03 marks)
8(a) Derive lens maker’s formula. (06 Marks)
(b) Explain how focal length of a convex lens is determined by Bassel’s method and using lensometer. (06 Marks)
(c) What are aspheric mirrors? (03 Marks)
(d) What is photoelectric effect? Explain Einstein’s photoelectric equations. (05 Marks)

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