Electrical Engineering Materials Question Paper of 3rd Semester Electrical(D) Download Previous Years Question Paper 9

S.B. Roll No.______

ELECTRICAL ENGINEERING MATERIALS

3^rd Exam/Elect/5208/May’10

Duration: 3 hrs.

Section-A

1.     Fill in the blanks

a.     In insulators the temperature coefficient of resistance is _____

b.     Brass is an ________ of copper.

c.      The conductors are stranded to improve

d.     A rectifier converts ac into ______

e.      Varnishes are used for impregnation of _______

f.       PTFE stands for________

g.     Expansion of CRGO is _______

h.     The process of adding sulphur in rubber to make it hard is called _______

i.       By using thin laminations __________ losses are reduced.

j.       Humidity decreases the ________ of insulators.

Section –B

2.       

a.     How can we select three types of electrical engineering materials on the basis of band theory.

b.     Explain the various properties of low resistivity conducting materials.

c.      Write any three application of each

                                                             i.      Aluminum

                                                           ii.      Steel

d.     With neat sketch explain the working of P type semiconductor.

e.      Explain the various characteristics of sulphurhexfluoride gas used as insulator

f.       With neat figure explain the working of thermocouple.

g.     With figures explain the three different types of tungsten filaments

h.     Define magnetic flux density and magnetizing force and derive relation between them.

Section –C

Note: Attempt any three questions

3.     With phasor diagram derive an expression for dielectric loss of insulator.

4.     Resistance of a conductor is 80 ohms at zero degree C find its resistance at 100 degree C. if the temperature coefficient of material is 0.0043 at zero degree C.

5.     In tabular form differentiate between applications and character of soft and hard magnetic materials.

6.     Explain the various materials used for making core, winding, bushing and tank of transformer.

7.     Write short note on

a.     Superconductivity

b.     ACSR

c.      Eddy current loss

d.     Application of mica