Attempt any five from the following:-

1 (a)
Explain why we see beautiful colour in thin film when it is exposed to sunlight.

3 M

1 (b)
Why would you recommend use of optical fibre in communication system?

3 M

1 (c)
Draw the energy level diagram of He-Ne laser. What is its wavelength in visible range?

3 M

1 (d)
Calculate the De-Broglie wavelength of proton travelling with a velocity equal to 1/20

(Mass of proton = 1.674 x 10

^{th}velocity of light.(Mass of proton = 1.674 x 10

^{-27}kg)
3 M

1 (e)
The susceptibility of a paramagnetic material at 300 K is 3.7x10

^{-3}. Find its relative permeability at 300 K.
3 M

1 (f)
State and explain Ohm's law for magnetic circuit.

3 M

1 (g)
Define and name different ranges of vacuum in terms of pressure.

3 M

2 (a)
Explain with neat figure construction and working of Rotary pump. For which vacuum range is it used?

8 M

2 (b)
Write full form of LASER. Explain three main processes involved in the production of LASER with appropriate figures.

7 M

3 (a)
Derive the formula for numerical aperture for a step index fibre. Calculate the Acceptance angle for an optical fibre given that refractive index of core is 1.45 and refractive index of cladding is 1.4.

8 M

3 (b)
Explain the construction and working of semiconductor diode laser with proper sketches. What are merits and demerits of this laser?

7 M

4 (a)
In a Newton's ring experiment the diameter of the 10

^{th}dark ring changes from 1.4 cm to 1.27 cm when a liquid is introduced between the lens and the plate. Calculate the refractive index of the liquid.
5 M

4 (b)
Using the uncertainty principle show that an electron cannot pre-exist in free state in a nucleus.

5 M

4 (c)
A solenoid consisting of 500 turns and carrying 4 Amp current is 0.5 m long. Calculate:

(i) Magnetomotive force

(ii) Flux density B

(i) Magnetomotive force

(ii) Flux density B

5 M

5 (a)
A diffraction grating used at normal incidence gives a line 5400Å in certain order super-imposed on another line 4050Å of the next higher order. If the angle of diffraction is 30°, how many lines/cm are there on the grating?

5 M

5 (b)
Derive one dimensional time dependent Schrodinger equation for matter waves.

5 M

5 (c)
Explain construction and working of Atomic force microscope.

5 M

6 (a)
Explain the experimental method of determination of wavelength of spectral line using diffraction grating.

5 M

6 (b)
An electron is bound in one dimensional potential box with width 2.5Å. Assuming the height of the box to be infinite, calculate the first two permitted energy values of the electron.

5 M

6 (c)
Discuss the importance of molecular modelling in bio-physics study.

5 M

7 (a)
White light falls normally on a soap film of thickness 5x10

^{-5}cm and of refractive index 1.33. Which wavelength in the visible region will be reflected most strongly?
5 M

7 (b)
How the phenomenon of holography can be explained with interference and diffraction of light?

5 M

7 (c)
What are hard and soft magnetic materials? Explain these materials using their characteristic properties and applications.

5 M

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