ENGINEERING MATERIALS IN EE QUIZ

Dielectric constant for vacuum is

infinity.

0.

100.

1.

TRUE ANSWER : ?
YOUR ANSWER : ?

In order to minimise loss due to hysteresis, the magnetic material should have

high resistivity.

high retentivity.

large B-H loop area.

low hysteresis coefficient.

TRUE ANSWER : ?
YOUR ANSWER : ?

A ferromagnetic core subjected to cycles of magnetisation will exhibit hysteresis when the cycle is

alternating.

pulsating.

rotating.

/ >(A), (B), and (C) are all correct.

TRUE ANSWER : ?
YOUR ANSWER : ?

It is difficult to magnetize steel because it has

low permeability.

high permeability.

low susceptibility.

high permittivity.

TRUE ANSWER : ?
YOUR ANSWER : ?

Cryogenics is a branch of science dealing with which of the following?

Friction and wear.

High temperature.

Low temperature.

Crystal growth.

TRUE ANSWER : ?
YOUR ANSWER : ?

A degaussing is the process of

removing gases from materials.

remagnetising metallic parts.

demagnetising metallic parts.

removal of magnetic impurities.

TRUE ANSWER : ?
YOUR ANSWER : ?

How many classes of insulating materials are there?

7.

5.

8.

6.

TRUE ANSWER : ?
YOUR ANSWER : ?

________ is the most detrimental impurity in the magnetic materials

Sulphur.

Carbon.

Nitrogen.

Oxygen.

TRUE ANSWER : ?
YOUR ANSWER : ?

In electrical machines the material preferred for pole shoes of electromagnets is

lead.

copper.

aluminium.

pure iron.

TRUE ANSWER : ?
YOUR ANSWER : ?

Which of following material has least value of dielectric constant?

Oil.

Paper.

Ceramics.

Glass.

TRUE ANSWER : ?
YOUR ANSWER : ?

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