Solapur University Solid State Physics B.Sc 05th Sem 2014 Question Paper

Solapur University Previous Years Question Papers
B.Sc. III (Semester – V) Examination, 2014
PHYSICS
Solid State Physics (Special Paper – X)
Day and Date : Friday, 11-4-2014 Max. Marks : 50
Time : 3.00 p.m. to 5.00 p.m.
N.B.: 1) All questions are compulsory.
2) Figures to the right indicate full marks.
3) Draw a neat and labelled diagrams wherever necessary.
4) Use of log table and calculator is allowed.
1. Select the correct alternative : 10
i) The temperature below which certain materials are antiferromagnetic is called
a) Debye temperature b) Curie temperature
c) Weiss temperature d) Neel temperature
ii) The most important characteristics of ferromagnetic materials is
a) Spontaneous magnetization b) Neel temperature
c) Faraday’s temperature d) Demagnetization temperature
iii) The temperature at which a metal becomes a superconductor is called
a) Curie temperature b) Neel temperature
c) Critical (Transition) temperature d) None of the above
iv) For a metal to be considered as a superconductor, it has to exhibit
a) Only zero resistivity
b) Only Meissner effect
c) Zero resistivity and Meissner effect both
d) Only Josephson effect
v) Bragg’s law in terms of reciprocal lattice vector G is
a) 2K . G + K2 = 0 b) 2k . G + G2 = 0
c) G . G + 2K . 2 K = 0 d) 2G. G + K . K = 0

vi) If a, b, c are the primitive vectors in direct lattice then a*, the primitive vectors in reciprocal lattice is proportional to
a)
a.b c
a c
×
×
b)
a.b c
a b
×
×
c)
a.b c
b c
×
×
d)
b c
a.b c
×
×
vii) The range of electrical to thermal conductivity ( ) K
σ was found from ________
at room temperature.
a) 6.7×1010 to 7.5×1010 b) 4.5×1010 to 5.6 ×1010
c) 2.8 ×1010 to 3.7 × 1010 d) 1.2×1010 to 2.8 × 1010
viii) In metals, the forbidden energy gap is __________eV.
a) 0 b) 1 to 0.75
c) 3 to 4 d) 5 to 6
ix) According to Sommerfeld’s model of metal, energy of electron En = ________.
a) 2 2
2 2
8h L
n m
b) 2 2
2 2
8n L
m h
c) 2 2
2 2
8m h
n L
d) 2
2 2
8mL
n h
x) In primitive cell, the number of lattice points per unit cell will be equal to
a) 4 b) 3
c) 2 d) 1
2. Answer any five of the following : 10
i) What is principle of powder method of X-ray diffraction ?
ii) What is Fermi Energy ?
iii) What are the properties of ferrimagnetism ?
iv) What is Anti-Ferromagnetism ?
v) Explain the term superconductivity.
vi) What is soft superconductors ?

3. A) Answer any two of the following : 6
i) Describe free electron gas model of the metal.
ii) Explain the effect of magnetic field on superconductor.
iii) Calculate the lattice spacing between (101) planes in an orthorhombic
lattice where a = 2.4 A°, b = 3.1 A°, C = 2.9A°.
B) Write a note on ‘hysteresis loop’ in ferromagnetic materials. 4
4. Answer any two of the following : 10
i) Discuss Fermi-Dirac distribution of an electron in the metal.
ii) Show that volume of the unit cell of the reciprocal lattice is inversely
proportional to the volume of the unit cell of the direct lattice.
iii) Explain in short the formation of energy bands in solid.
5. Answer any one of the following : 10
i) What do you understand by packing fraction in crystals ? Show that the packing fraction for bcc and fcc structures are 82 & 8π 3 π respectively.
ii) Explain Hall effect. Obtain an expression for Hall voltage, Hall coefficient, Mobility of charge carrier and Conductivity of the metal on the basis of Hall

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