Electrical Engineering Materials Question Paper of 3rd Semester Electrical(D) Download Previous Years Question Paper 7

B. Roll No.______

ELECTRICAL ENGINEERING MATERIALS

3^rd Exam/Elect/5243/May’06

Duration: 3 hrs.

1.     Choose the correct one

a.     Resistivity of metals is expressed in terms of

                                                             i.      µ Ohm

                                                           ii.      µ Ohm/cm

                                                        iii.      µ Ohm

                                                        iv.      µ Ohm-cm/̊C

b.     thermocouple works on which of the following effects.

                                                             i.      Thomson effect

                                                           ii.      Seeback effect

                                                        iii.      Peltier effect

                                                        iv.      Joule effect

c.      When a ferromagnetic substance is magnetized small changes in dimensions occur. Such a phenomenon is known as

                                                             i.      Magnetic hysteresis

                                                           ii.      Magnetic expansion

                                                        iii.      Magnetostriction

                                                        iv.       Magneto- colorization

d.     Which of the following properties has lower value for copper as compared to aluminum?

                                                             i.      Specific gravity

                                                           ii.      Melting point

                                                        iii.      Resistivity

                                                        iv.      All of the above

e.      Soft magnetic materials are widely used in

                                                             i.      Meters

                                                           ii.      Transducers

                                                        iii.      Transformer cores

                                                        iv.      Televisions

State true or false

i.       Ferrites are generally hard and brittle

j.       Aluminum is easily soldrable

k.      Age hardening increases the resistivity of an alloy.

l.       The crystal structure of silicon is diamond.

m.  Bronze is an alloy of copper zinc and tin.

Section –B

Note: attempt any five questions

2.              

a.     Explain in the following terms:

                                                             i.      Valence band

                                                           ii.      Conduction band

b.     What is superconductivity? Explain.

c.      Explain the following:

                                                             i.      Dielectric loss

                                                           ii.      Dielectric strength

d.     What do you mean by volume resistivity? Explain

e.      What are different applications  of semi conducting materials?

f.       What do you mean by Magnetostrication in ferromagnetic material? Explain  

g.     Discuss the properties of Bakelite.

                                                             i.      What do you mean by permeability? Explain

                                                           ii.      Define abrasion resistance

Section –C

Note: Attempt any three questions

3.     What do you mean by resistivity? Explain the factor affecting resitivity.

4.     Discuss properties and applications of following material

a.     Air

b.     Bitumen

5.     Explain properties and applications of following soft magnetic materials

a.     Nickel iron alloy

b.     Soft ferrites

6.     Write the short note on

a.     Thermoplastic

b.     Thermocouple

7.     Explain properties and application of following materials

a.     Steel

b.     Polyvinyl chloride