USN 10PHY12/22
First/Second Semester B.E. Degree Examination, January
2013
Engineering Physics
Time: 3 hrs. Max.
Marks:100
Note: 1. Answer any FIVE full
questions, choosing atleast two from each part.
2. Answer all objective type
questions only in OMR sheet page 5 of the answer booklet.
3. Answer to objective type questions
on sheets other than OMR will not be valued.
4. Physical constants: h = 6.626×10-34
Js, c = 3×108 m/s, me = 9.1×10-31 kg,
k
= 1.38×10-23 J/K, ε0 = 8.854×10-12 F/m
PART-A
1 a. i) Electrons behaves as
a wave because they can be
A) Diffracted by a crystal B) Deflected by magnetic
field
C) Deflected by electric field D) Ionise a gas
ii) In a blackbody radiation
spectrum, the Wien’s distribution law is applicable only for
A) Longer wavelength B) Shorter wavelength C) Entire wavelength D) None of these
ii) If the momentum of a particle is
increased to four times, the de-Broglie wavelength is
A) become twice B) become for times C) become one-fourth D) become half
iv) If the group velocity of a particle
is 3×106 m/s, its phase velocity is
A) 100 m/s B) 3×106
m/s C) 3×108 m/s
D) 3×1010 m/s (04
marks)
b. Describe Davisson-Germer experiment to prove the dual nature of
matter waves. (06marks)
c. Derive
de-Broglie wavelength using Group velocity.
(06 marks)
d. Compare the energy of a photon
with that of a neutron when both are associated with wavelength of 1 Å. Given
that mass of neutron is 1.678 × 10 -27 kg. (04 marks)
2 a. i) According to Max Born
approximation, |y|2
represents
A) Energy density B) Particle density C) Probability density
D) Charge density
ii) The wavefunction is acceptable if it
is
A) Finite everywhere B)
Continuous everywhere
C) Single valued everywhere D)
All of these
iii) The first permitted energy level is
called
A) Excited energy level B) Zero
point energy C) Ground level
D) None of these
iv) The wavefunction for the motion of
particles in one dimensional potential box of length ‘a’ is given by yn
= D sin npx/a
where ‘D’ is normalization constant. The value of ‘D’ is
A)
B)
C) a D)
(04
Marks)
b. Set up time independent one
dimensional Schrödinger wave equation. (06 Marks)
c. What is a wave function? Explain the properties of a
wave function. (04 Marks)
d. A quantum particle confined to one dimensional box of
width ‘a’ is in its first excited state. What is the probability of finding the
particle over an interval of (
marked symmetrically at the centre of
box.
(06 marks)
3 a. i) The
classical value of molar specific heat of a conductor is
A) 3/2 R B) ½ R C)
3R D) 5/2
R
ii) For ordinary metals,
the resistivity versus temperature curve at T = 0,
A) has a positive intercept B)
has a negative intercept
C) goes through the origin D)
none of these
iii) Ohms law relates to the electric
field E, conductivity s and current density J as
A) J = E/s B)
J = sE2 C) J = s/E D) J
= sE
iv) If the Fermi energy of
silver is 5.5 eV, the Fermi velocity of conduction electron is
A) 0.98 × 106 m/s B)
1.39 × 106 m/s C) 2.46 × 105 m/s D) None of these (04 Marks)
b. Obtain the expression for
electrical conductivity on the basis of free electron theory of metals. (06
Marks)
c. Explain how quantum free
electron theory succeeds in overcoming the drawbacks of classical free electron
theory. (06 marks)
d. Calculate the probability of
an electron occupying an energy level 0.02 eV above the Fermi level and 0.02 eV
below the Fermi level at 200 K. (04
marks)
4 a. i) Hysteresis loss occurs when the magnetic material is
subjected to
A) DC voltage B) AC voltage C) Both AC and DC voltage D) none of these
ii) Which one of the following is a
piezoelectric material?
A) Lead B) Mica C) Iron D)
Quartz
iii) If two electric charges are q separated by a distance L, dipole
moment of the system is
A) q/L B) L/q C) qL D)
q/L2
iv) The polarization that occurs in the frequency range 1013
to 1016 Hz is
A) Electronic B) Orientational C) Ionic D) Space charge (04 Marks)
b. Derive an expression for
internal field in the case of one dimensional array of atoms in dielectric
solids. (07
Marks)
c. What are soft magnetic
materials? Discuss their properties. (05 Marks)
d. A NaCl crystal is subjected to
an electric field of 1000 V/m and the resulting polarization is 4.3×10-8
c/m2. Calculate the
static dielectric constant of NaCl. (04
Marks)
PART-B
5 a. i) Emission of a photon by an excited atom due to interaction
of external energy is called
A) Spontaneous emission B) Stimulated emission C) Induced absorption
D) Light amplification
ii) ) Let n1 be the number density of lower energy E1
and n2 be the number density of higher energy E2, if n2>n1 is called
A) Thick population B) Inverted population C) Normal population D) No population
iii) The relation between Einstein’s coefficient’s A and B is
A)
B)
C)
D)
iv) Pumping process used in diode laser is
A) Optical pumping B) Forward bias C) Electric discharge D) None of these
(04 Marks)
b. Obtain an expression for
energy density of radiation under equilibrium condition in terms of Einstein
coefficient. (07 Marks)
c. Describe the recording and
reconstruction processes in holography, with the help of suitable diagrams. (05 Marks)
d. A ruby laser emits pulse of 20
ns duration with average power per pulse being 100 kW. If the number of photons
in each pulse is 6.981 × 1015, calculate the wavelength of photons. (04 Marks)
6 a. i) Superconductors are
A) diamagnetic B) paramagnetic C)
ferromagnetic D) antiferromagnetic
ii) In a single mode fiber, the diameter of
the core is nearly equal to
A) 125 mm B) 100 mm C) 50 mm D) 10 mm
iii) Attenuation in the optical fiber causes due to
A) Absorption B) Scattering C) Dispersion D) All the three
iv) Meissner effect will take place in
A) Solid B) Super conducting magnet C) Maglev vehicle D) MRI (04 Marks)
b. Obtain an expression for numerical aperture and arrive
the condition for propagation. (06
Marks)
c. Give a brief account of SQUID. (06 Marks)
d. A fiber 500m long has an input
power of 8.6 mw and output power 7.5 mw. What is the loss specification in
cable? (04
Marks)
7 a. i) Four types of Bravais lattices are observed in
A) Rhomohedral system B) Orthorhombic system
C) Triclinic system D) Monoclinic system
ii) A plane intercepts at a, b/2, 2c in a
simple cubic unit cell. The miller indices of the plane are
A) (214) B) (241) C)
(421) D) (124)
iii) The packing factor for fcc structure is
A) 52% B) 68% C)
92% D) none of these
iv) The miller indices of the plane parallel to the x and y axes
are
A) (100) B) (010) C) (001) D)
(111) (04 Marks)
b. With a neat figure, explain the structure of diamond and show that atomic
packing factor of diamond is 0.34. (08 Marks)
c. How do you find Miller indices
of a given plane? (04 Marks)
d. The minimum order of Bragg’s
reflection occurs at an angle 200
in the plane [212]. Find the wavelength of X-ray if lattice constant is 3.615
Å. (04 Marks)
8 a. i) The state of matter around nanosize is known as
A) solid state B) liquid state C) mesoscopic state D) macroscopic
state
ii) In a carbon nanotubes, the bond between the carbon atoms is
A) metallic B)
ionic C) covalent D) hydrogen
iii) Elastic behavior of the liquid is characterized by its
A) Young’s modulus B) Rigidity
modulus C) bulk modulus D)
Poisson’s ratio
iv) Ultrasonic waves are produced by
A) Electromagnetic induction B) Inverse piezoelectric effect
C) Electronic tuning fork D)Piezoelectric effect (04 Marks)
b. Write a note on carbon
nanotubes. Discuss the various quantum
structures. (08 Marks)
c. Explain the principle and
method of nondestructive testing of material using ultrasonics.
(08 Marks)
1 comment:
Thanks.Almost same questions asked this time.Kindly give multiple choice question answers.
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