USN 10PHY12/22
First/Second Semester B.E. Degree Examination, December 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)
The law which failed to account
for shorter wavelength region of blackbody radiation spectrum is
A) Wien’s law B) Rayleigh-Jean’s
law C) Planck’s law D) Maxwell’s law
ii) The group velocity of the particle is 3×106
m/s, whose phase velocity is
A) 6.06×106 m/s B)
3×1010 m/s C) 3×106
m/s D) 1.5×1010 m/s
ii) Photoelectric effect
establishes
A) wave nature of light B)
particle nature of light C) dual nature
of light D) None of these
iv) The Compton wavelength is given by
A) h/m0C2 B) h2/m0C2
C) h/m0C D) h2/2m0C
(04
marks)
b. Derive de-Broglie wavelength using group
velocity. (05marks)
c. Describe Davisson and Germer experiment for
confirmation of de-Broglie hypothesis (07 Marks)
d. Find the de-Broglie wavelength of particle of
mass 0.65 MeV/C2 has a kinetic energy 80 eV. (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 product of uncertainty between angular momentum and angular displacement is
A) ≥ ħ/2p B) ≥ ħ /4p C) ≤ ħ /4p
D) ≥ ħ /2
iii) The ground state energy of an electron in an one dimensional
infinite potential well of width 2Å is 16 eV. Its energy in third excited state
is
A) 32 eV B) 64 eV C) 144 eV D) 256 eV
iv)
The wavefunction is acceptable if it is
A) Finite everywhere B)
Continuous everywhere
C) Single valued everywhere D) All of
these
(04
Marks)
b. State
and explain Heisenberg’s uncertainty principle and prove that nuclei do not
contain electron. (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) According to quantum free electron theory, the energy level in a
metal are
A) Continuous B) Discrete C)
Overlapping D) None
iv) The fermi
factor for E = EF at T > 0K is
A) 1 B) ½ C) 0 D)
2
(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) In the inverse piezo electric effect,
A) Ultrasonic waves are produced B) electromagnetic
waves are produced
C) microwaves are produced D) none of the above
ii) If
two electric charges are q, separated by a distance L, the dipole moment of the
system is
A)
q/L B) L/q C) qL D)
q/L2
iii) The
relation between B, M and H is
A)
H = m0(M+B) B) M = m0(H+B) C) B = m0(H+M) D) None of these
iv) The
relative permeability for diamagnetic materials is
A) Slightly
greater than one B) Zero C) less than one D) very much greater than one (04
Marks)
b. Derive the expression for internal field in
solids. (08
Marks)
c. Distinguish between hard and soft magnetic
materials. (04
Marks)
d. The atomic weight and density of sulphur
are 32 and 2.08 g/cc respectively. The electronic polarizability of the atom is
3.28×10-40 F.m2. If sulphur solid has cubic symmetry,
what will be its relative permittivity? (04
Marks)
PART-B
5 a. i) The emission of photon without
aided by any external agency is called
A) Light amplification B) Induced absorption C) Stimulated emission D) Spontaneous emission
ii) The life time of an atom at the
ordinary excited state is of the order of
A) few milli second B) few nano second C) few micro second D) Unlimited
iii) Pumping
technique used in He-Ne gas laser is
A) Forward bias B)
Optical pumping C) Electrical discharge D) High injection current
iv) From
a broken hologram which is 10% of the original, if reconstruction of image is
being done, then
A)
Only 10% of information of the object can be obtained
B) Complete information of the
object is obtained
C) No information of the object can be
obtained D) None of these (04 Marks)
b. Obtain an expression for energy
density of radiation under equilibrium condition in terms of Einstein
coefficient. (06Marks)
c. Describe the recording and
reconstruction processes in holography, with the help of suitable diagrams. (06
Marks)
d. Calculate on the basis of Einstein’s
theory the number of photons emitted per second by He-Ne laser source emitting
light of wavelength 6328Å with an optical power 10 mW. (04 Marks)
6 a. i) The critical temperature of
mercury is
A) 4.2 K B)
6.2 K C) 7.8 K D) 20 K
ii) Attenuation
in the optical fiber causes due to
A) Absorption B) Scattering C) Dispersion D) All the three
iii) Numerical
aperture of an optical fiber depends on
A) Diameter of the fiber B) Acceptance angle C) Critical angle D) hcore
material
iv)
Superconductors are
Diamagnetic B) paramagnetic C) ferromagnetic
D) antiferromagnetic (04
Marks)
b. Discuss BCS theory of superconductor.
Explain SQUID. (07
Marks)
c. Describe the point to point
communication system, with the help of block diagram. (05 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) For every rotation by angle q in Bragg’s spectrometer, detector
turns by an angle
A) q B)3q C) 4q D) 2q
ii) APf of diamond crystal structure is
A) 0.68 B) 0.74 C) 0.52 D) 0.34
iii)
In a simple cubic
lattice the ratio d100:d110:d111 is
A) 6:3:1 B) √3:√6:1 C) 6:3:√2 D) √6:√3:√2
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. Discuss the Bravais lattice and any
five crystal systems with the help of illustrations. (07Marks)
c. How do you find Miller indices of a
given plane. (05Marks)
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) Testing of a product without causing
any damage is called
A) minute testing B) destructive testing
C) non-destructive testing D) random testing
ii) The
state of matter around the nanosize is known as
A) Liquid state B) Plasma state C) Mesoscopic state D)
Solid state
iii) In
a carbon nanotubes, the bond between the carbon atoms is
A) metallic B)
ionic C) hydrogen D) covalent
iv) A
bulk material (three dimensions) reduced in two directions is known as
A) Quantum dot B)
Quantum particle C) Film D) Quantum wire (04 Marks)
b. What are Nanomaterials? Explain carbon
nanotubes and their physical properties. Mention few applications of carbon
nanotubes. (08
Marks)
c. Explain the principle and method of
nondestructive method of testing of material using ultrasonics. (08 Marks)
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