Cochin University of Science and Techology (CUST) 2007-1st Year B.Tech engineering physics - Question Paper

BTECH 1st YEAR exam MAY 2007
ENGINEERING PHYSICS Max marks:100
Time:3 Hrs

PART A

1. a) What is a zone plate? Compare zone plate with a convex lens.

b) State & discuss Rayleigh’s criterion for limit of resolution.

c) discuss the basic principles of laser action.

d) What is meant by mode of propagation in optical fibres? Differentiate b/w step
index single mode optical fibre & step index multimode optical fibre.

e) elaborate the properties of nuclear forces?

f) discuss the concepts of vector atom model.

g) What is a Half wave plate? compute the thickness of a half wave plate of quartz for
a wavelength of 5000 Angstrom. Here refractive indices for extra ordinary rays
=1.553 & refractive indices for ordinary rays = 1.544.

h) describe the subsequent terms
1) crystal lattice 2) unit cell 3) packing factor 4) co-ordination number
5) miller indices
PART B

2. a) What is a plane transmission grating?

b) find the expression (a+b)sinx = n lambda

c) A diffraction grating used at normal incidence provide a green line wavelength = 5400
Angstrom in a certain order super imposed on the violet line, wavelength = 4050
Angstrom of the next higher order – if the angle of diffraction is 30 degrees obtain the
number of lines per centimeter of the grating.

d) What is dispersive power of a grating? find an formula for dispersive power.

OR

3. a) find the condition for a thin film to appear bright in reflected light

b) discuss colours of thin films.

c) A parallel beam of light wavelength = 5890 Angstrom, is incident on a glass plate
such that angle of refraction into the plate is 60. compute the smallest thickness of
the plate which will make it appear dark by reflection. ( refractive index of
glass = 1.5)

4. a) discuss the structure & working of He-Ne laser.

b) Mention the applications of ultrasonics.
OR

5. a) Derive an expression for Numerical Aperture of an optical fibre.

b) discuss the term Acceptance angle & Acceptance cone.

c) An optical fibre has a Numerical Aperture of 0.20 & a cladding refractive index of
1.59. Determine the acceptance angle for the fibre in water which has a refractive
index of 1.33.

6. a) Derive Time independent schrodinger formula.

b) What is the physical significance of wave function?

c) State & discuss Heisenberg’s uncertainty principle.
OR

7. discuss the subsequent
1) Seeman effect 2) Stark effect 3) Raman effect 4) Thermo nuclear reactions 5)
Nuclear reaction cross part. Derive an expression for magnetic moment of orbital
electron.

8. a) discuss Meissner effect & Isotope effect.

b) Differentiate b/w kind I & kind II Super conductors.

c) What is meant by SQUIDS?

d) Mention any 1 of its application.
OR

9. a) discuss the production of X- rays by using Coolidge Tube.

b) State & derive Bragg’s legal regulations for diffraction in crystals.

c) Using Bragg’s X- ray spectrometer, the glancing angle for the 1st order spectrum
was observed to be eight degrees. If the distance b/w 2 consecutive crystal planes is
2.82 Angstrom. obtain the wavelength of X- ray used.
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Earning:   Approval pending.