25.

26.

27.

28.

29.

30.

31.

32.
33.

34.

35.

Section D

(Prob ಗಗ್‌
lems- write all relevant formulas. All important steps carry separate marks.
Answer any four questions. Each question carries 4 marks.

A soa 5 7-7 ۱
light ae 5 x 10-6 cm thick is viewed at an angle of 35° to the normal. Find the wavelength of
in the visible spectrum which will be absent from the reflected light. Given 1 = 1.33 ?

What i i i
١ at is the radius of the 1*t half period zone in a zone plate behavior like, a convex lens of focal
ength60cm for light of wavelength 6000A ?

Calculate the thickness of (i) quarter wave plate(ii) a half wave plate. Given that
Hy = 1 .978, 1, = 2.656 and A = 590nm.

Show that areas of half period zones are equal.

Calculate the angle of acceptance of a given optical fiber, if the refractive indices of the core and
the cladding are 1.563 and 1.498 respectively.

The critical angle of incidence for total reflection in case of water is 48°. What is its polarization
angle ? What is the angle of refraction corresponding to the polarization angle ?

In Fraunhoffer diffraction pattern due to a narrow slit a screen is placed 2m away from the lens to

obtain the pattern. If the slit width is 0.2 mm and the first minimum lie 5mm on either sides of the
central maximum, find the wavelength of light.

(4x 4 = 16 marks)
Section E

Essays. Answer in about two pages.
Answer any two questions. Each question carries 10 marks.

Discuss the Fraunhoffer diffraction pattern due to a single slit. Draw the intensity distribution ?

Write principle of holography ? Describe the recording and rerecording process in holography with
the help of suitable diagrams.

What are Newtons ring ? derive an expression for the radius of the nth dark ring formed by the
reflection also by transmitted light.

Explain the rectangular propagation of light on the basis of Fresnels half period zone.

(2 x 10 = 20 marks)