BBA Iind SEMESTER EXAMINATION 2008-09 s56

B.Sc (Hons) Physics/Electronics II (Second) Semester Examination 2014-15

Course Code:BAS209 Paper ID:0982411

Optics

Time: 3 Hours Max. Marks: 70 Max Marks: 75

Note: Attempt six questions in all. Q. No. 1 is compulsory.

1. Answer any five of the following (limit your answer to 50 words). (4x5=20)

a) What do you understand by Nodal points Illustrate them by a neat diagram in case of a thick lens?

b) Explain the construction and working of a Huygens eye-piece.

c) What is interference? Define coherent sources. Discuss why two independent sources of light of some wavelength can not show interference?

d) Write a short note on Newton’s rings.

e) What is diffraction of light? Distinguish between Fresnel and Fraunhofer classes of diffraction.

f) Discuss phenomenon of double refraction.

g) Explain Rayleigh’s criterion for resolution.

h) Write a short note on colour of thin films.

2. State and explain Fermat’s principle of extremum path and analyse a case where the actual path of light may be maximum. (10)

3. a) Using Nodal Slide describe how will yu verify the formula

experimentally. (5)

b) Show that in interference with two coherent sources of any intensity ratio, the intensity variation in the fringes is of the cosine () form. (5)

4. Discuss construction and theory of Rayleigh refractometer. Discuss its applications. (10)

5. Draw a neat diagram of Michelson’s interferometer. Explain the use of a compensating glass plate. State the conditions for obtaining: (10)

a) Circular fringes

b) White light fringes

6. Discuss the construction and working of a zone plate. Derive a formula for its focal length and show that it has multiple foci. (10)

7. What do you understand by optical rotations? Show how Fresnel’s theory explain optical rotation? What experimental evidence is there in support of the theory? (10)

8. Write short notes on the following: (5+5)

a) Plane diffraction grating

b) Half wave plate