LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

B.Sc. DEGREE EXAMINATION – PHYSICS

XC 10

THIRD SEMESTER – April 2009

PH 3500 – OPTICS

 

 

 

Date & Time: 06/05/2009 / 9:00 – 12:00  Dept. No.                                                   Max. : 100 Marks

 

 

SECTION – A

Answer all the questions.                                                                    10 × 2 = 20 Marks

 

1. What do you mean by Nodal points and Nodal planes?
2. What is chromatic aberration of a lens?
3. Compare the interference fringes produced by biprism with those produced by Lloyd’s mirror.
4. How would you test the planeness of a surface optically?
5. Using a plane transmission grating set for normal incidence, the sodium yellow doublet is just resolved in the second order spectrum. What is the minimum number of lines present on the grating? The yellow sodium doublet has a mean wavelength of 5893A˚ with 6A˚ as the width between the two lines.
6. Distinguish between Fresnel and Fraunhoffer diffraction.
7. What is a half – wave plate?
8. State the law of Malus.
9. What do you understand by stimulated emission? Mention its importance.
10. What do you understand by nonlinear optical phenomenon?

SECTION – B

Answer any four questions.                                                               4 × 7.5 = 30 Marks

11. (a) What is the advantage of using matrix method in optics?             (2)

 

(b)        Determine the matrix that will produce the effect of refraction on a ray of

light.                                                                                                       (5.5)

12. Describe Fresnel’s biprism method to determine the wavelength of light .  (7.5)
13. (a) What is a zone plate?                                                                              (2.5)
    • What are the differences between a zone plate and a convex lens? (5)
14. How would you produce and detect elliptically polarized light?           (4.5+3)
15. Give the theory of spontaneous and stimulated emission of radiation. Determine Einstein’s                                                                                                                 (7.5)

 

 

SECTION-C

Answer any four questions.                                                               4 × 12.5 = 50 Marks

16. (a) Describe the construction and working of a Ramsden eyepiece.       (3+5.5)

(b)        Explain how chromatic and spherical aberrations are minimized in this                    eyepiece.                                                                                                      (2+2)

17. (a) Describe the construction and working of Michelson’s interferometer.

(3+5.5)

(b)          How would you use it to determine the wavelength of light?                (4)

18. (a) What do you understand by resolving power of an optical instrument?

(2)

(b)        Explain Rayleigh criterion for resolution and apply it to find the resolving power of a prism.                                                                                                   (4+6.5)

19. (a) Define specific rotatory power.                                                                 (2)

(b)        Explain how specific rotatory power of a sugar solution is determined

using Laurent’s half shade polarimeter.                                                       (8.5)

(c)        A 20 cm long glass tube containing sugar solution rotates the plane of

polarization by 11˚.If the specific rotation of the solution is   66 ˚,

calculate  the concentration of the solution.                                                 (2)

20. (a) Derive threshold condition for laser action.                                               (4)

(b)        Explain the principle and working of a He – Ne laser.                               (8.5)

 

 

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