COMBINED I & II SEMESTER B.TECH. ENGINEERING
DEGREE
MODEL EXAMINATION 2009
EN2K 103 A ENGINEERING PHYSICS (A)
Time : 3 hours
Max. marks : 100
Answer all questions.
PART A
I) 1.What is Fermi level.Find the position of Fermi level in P-type
semiconductor.
2. Explain AC and DC Josephson effect..
3.Determine the refractive index of gases using Michelson
Interferometer.
4. Explain the resolving power of Plane diffraction grating.
5. Explain the method of detection of circularly and elliptically
polarized light.
6. Derive an expression for numerical aperture of a step index fiber.
7. A proton is confined to a nucleus of radius 5x10 -15 m .Calculate
its minimum uncertainty in its momentum. Also calculate the minimum
kinetic energy of the proton.
8. Explain the method of production of ultrasonic waves using
piezoelectric method.
PART B
II)
(A)1.
Write
short
notes
on
LED
and
LCD
(12 marks)
2. A semiconductor material of thickness 2 mm, breadth
10mm and length 100 mm is placed in a magnetic field of 0.5 T acting
perpendicular to its thickness. If a current of 0.1 A flows along its
length, calculate the Hall voltage developed. The Hall coefficient of the
specimen is 3.66 x 10-4m3/c.
(3 marks)
OR
(B)1. Explain BCS theory of Superconductivity.
marks)
(7
2.
Explain the working of Zener diode as a voltage
regulator.(6marks)
3. The band gap of Gallium Arsenide is 1.44 eV. Calculate its
wavelength during forward bias.
(2 marks)
III)
(A)1. Explain the construction and working of Michelson
Interferometer and determine the wavelength of a monochromatic light
usinf Michelson interferometer.
(12 marks)
2. A glass wedge of angle 0.01 radian is illuminated by a
monochromatic light of 6000 Ấ falling normally on it. At what distance
from the edge of the wedge will the 10th fringe be observed by the
reflected light.
(3 marks)
OR
(B)1. Explain the construction and working of a plane transmission
grating.
(8 marks)
2. Explain the formation of newtons ring and derive the
expression for the nth Dark ring.
(5 marks)
3/. Calculate the minimum number of lines per centimeter
in a 2.5 cm wide grating which will just resolve the sodium
lines (5890 Ấ and 5896 Ấ) in the second order spectrum.
(2 marks)
IV)
A) 1. Explain the construction and working of a half shade
polarimeter and explain how will you determine the specific rotation of a
substance.
(7 marks)
2. Determine the specific rotation of pure sample of sugar
solution ,if the plane of polarization is turned through 13.2 degree. The
length of the tube containing 10% sugar solution is 20 cm.
(8 marks)
OR
B) 1. Explain with a neat diagram the principle ,construction and
working of a semiconductor laser. What are its merits and demerits.
(7 marks)
2) Explain the principle of holography and what are its applications.
( 8 marks)
V) A) 1) Derive the energy eigen values and eigen function for a particle
in
a
one
dimensional
box.
(7 marks)
2) Find the energy of an electron moving in a one dimensional
infinitely high potential box of width 1 Ấ
(8 marks)
OR
B) 1) Give Planck’s hypothesis and derive the Planck’s law for black
body radiation.
(8 marks)
2) Derive Schrödinger’s time dependent equation..
*****************
(7 marks)