Total Number of Pages: 02
3rd Semester Regular/Back Examination 2017-18
ELECTRICAL ENGINEERING MATERIALS
Time: 3 Hours
Max Marks: 100
Answer Question No. 1 and 2 which are compulsory and any four from rest.
The figures in the right hand margin indicate marks.
Answer the following questions: multiple type or dash fill up type
A crystal is said to have a simple form if its all faces are
(i) Similar (ii) Dissimilar (iii) Partly similar (iv) Partly dissimilar
The converse of hardness is known as
(i) malleability (ii) toughness (iii) softness (iv) None of the above
A perfect conductor has
(i) Zero conductivity (ii) Unity conductivity
(iii) Infinite conductivity (iv) None of the above
Which of the following materials is preferred for transmitting electrical energy
over long distance
(iii) steel rein forced copper (iv) steel rein forced aluminum
The super conductivity is observed
(i) infrared frequency (ii) dc and low frequency (iii) ac and high frequency
(iv) Frequencies having no effect (v) None of the above
Thermionic emission occurs in
(i) vacuum tubes (ii) copper conductors (iii) ferrite cores (iv) transistors
Which of the following materials is not a semi conductor
(i) Silica (ii) Germanium (iii) Selenium (iv) Gallium-arsenide
The permeability of iron is around
(i) 500 (ii) 800 (iii) 1200 (iv) 2000
The materials having permanent electric moment are called
(i) anti- ferroelectric materials (ii) dielectrics
(iv) semi conductor materials.
When the temperature exceeds to a certain value called the Curie point, the
(i) Loses its ferro electric properties (ii) gains ferroelectric properties
(iii) either of the above
(iv) none of the above.
(2 x 10)
Answer the following questions: Short answer type
What do you mean by mixed bonding?
What is the difference between crystalline and non crystalline material?
Derive an expression for heat development a current currying conductor.
State the application of super conductors.
What do you understand by the term loss angle of dielectric?
What do you understand by paramagnetism and dimagnetism ?
What do you mean by magnetic anisotropy?
What do you mean by doping in semiconductors?
What is hall effect?
What is skin effect?
(2 x 10)