Electrical Engineering Materials Question Paper of 3rd Semester Electrical(D) Download Previous Years Question Paper 4

S.B. Roll No.______

ELECTRICAL ENGINEERING MATERIALS

3^rd Exam/EE/5208/Dec’07

Duration: 3 hrs.

Section-A

1.     Fill in the blanks

a.     Dielectric materials are basically ___________

b.     Nichrome is an alloy of ________ and _________

c.      The conductors should have _________ value of temperature co-efficient of resistance.

d.     ____________ impurity is added to pure semiconductor to obtain p-type semiconductor.

e.      The difference between the energies of conduction band and valence band is called ________

f.       Glass is _________ material.

g.     In electrical machines, varnish is mainly used in _______

h.     Magnetization curve is drawn between _______ and ______

i.       Working principle of the thermocouple is based upon ______ effect.

j.       The outer frame of small D.C machines are made of ________

Section –B

2.     Attempt any six questions.

a.     How materials are classified on the basis of energy band?

b.     Calculate the resistance of  an annealed copper conductor, 100 m long and having diameter of 0.09 cm. specific resistance of annealed copper is 1.724 x 10^-8 Ω-m

c.      State the advantages and disadvantages of aluminum as compared with copper.

d.     What is the effect of temperature on the conductivity of semiconductors?

e.      What is the effect of temperature on the conductivity of semiconductors?

f.       Mention the two main categories of plastics. Give example of each category.

g.     How the ceramic materials are classified?

h.     Define permeability and relative permeability.

i.       Write a short note on materials used for the construction of induction motor.

Section –c

          Note: Attempt any three questions.

3.     Discuss properties and applications of following:

a.     Bakelite

b.     Steel

4.       

a.     What is super conductor? Explain the applications of super conducting materials.

b.     Explain the terms dielectric loss and loss angle.

5.     Explain the following :

a.     N-type semiconductors

b.     P-type semiconductors

6.      

a.     State and explain the main factors which decide the selection of an insulating material for particular purpose.

b.     What are soft and hard magnetic materials?

7.     Write a short note on

a.     HRC fuse

b.     Soldering flux