Master of Science II (Physics-Materials Science)
Examination: Oct Nov 2016 Semester III (New CBCS)
SLR No. Day
Date Time Subject Name Paper
No. Seat No.
SLR SH
555
Wednesday
23/11/2016
02:30 P.M
To
05:00 P.M
Dielectric
Ferroelectric Properties
of Materials
C
XI
Instructions: Q. no. 1 and Q. no 2 are compulsory.
Attempt any three questions from Q. No.3 to Q. No. 7.
All questions carry equal marks.
Total Marks: 70
Q.1 Objective questions. 14
Select correct alternatives 06
In dielectrics, the power loss is proportional to
In ferroelectrics, the spontaneous polarization vanishes above a certain
temperature called
Transition temperature Debye temperature
Fermi temperature Curie temperature
In solids or liquid dielectrics, with external applied electric field, the
electronic polarization increase, the internal field
Increase Reduces
Remain unaltered None of the above
When mono-atomic gas is placed in uniform electric field the
displacement of the nucleus is proportional to
E2 E
E3 Independent of E
For a given dielectrics, as temperature increase, the ionic polarizability

Increases Decreases
Remains unaltered Keeps on increasing exponentially
Above curie temperature, the hysteresis loop of ferroelectric material merges
into
Parabola Straight line
Point Ellips
Page 1 of 2
Fill in the blanks 04
When polarization is uniform within the body the contribution to the
macroscopic field are from
Piezoelectric strain constant is defined as
PbZrO3 is an example of
Dielectric loss (tan is defined as
State true or false 04
All the crystal in ferroelectric state are NOT piezoelectric
Ferroelectrics with first order transition between the ferroelectric and the
para-electric state is distinguished by a continuous change of saturation
polarization at the transition temperature.
Spontaneous polarization in case of ABO3 type ferroelectric becomes zero
at ferroelectric-paraelectric transition temperature.
Materials with large electronic and ionic polarizabilities are used for making
dielectric capacitors.
Q.2 Write short notes 14
Double refraction and birefringence
Application of ferroelectric materials
Faraday effect
05
05
04
Q.3 Explain the different types of polarization mechanism in dielectrics? Sketch
their dependence on the frequency of the applied electric field.
Explain dielectric relaxation phenomena.
08
06
Q.4 Explain the term dielectric loss and dielectric breakdown. Also explain the
mechanism leading to dielectric breakdown.
Explain voigt effect
08
06
Q.5 Explain in detail local electric field at an atom in presence of external
electric field i.e. Elocal E0 E1 E2 E3 where E0 field produced by
fixed charges external to the body, E1 depolarization field, E2 Lorentz
field, E3 field from atoms inside cavity.
Explain phenomenon of spontaneous polarization in ferroelectric materials
08
06
Q.6 What are the chief characteristics of ferroelectric materials? How do you
establish existence of ferroelectricity in the material?
Explain ferroelectric domains with the help of suitable diagram.
08
06
Q.7 What do you mean by piezoelectricity? Explain phenomenological approach
to piezoelectric effects.
What are the applications of pyroelectric materials
08
06