Materials and Construction

Question 1

The behaviour of visco-elastic material is time dependent. This behaviour is common in __________ materials.

Answer 1

non-crystalline organic polymeric.

Question 2

Coke oven regenerators are made of __________ bricks.

Answer 2

fire clay

Question 3

Which of the following is universally employed as the low expansion metal in the bimetallic thermometer, which is an iron-nickel alloy containing 36% nickel and has very low co-efficient of expansion (l/20th of ordinary metals) ?

Answer 3

Invar

Question 4

Shock resisting steels should possess high

Answer 4

toughness

Question 5

The purpose of nitriding the steel is to

Answer 5

harden its surface.

Question 6

Ceramic recuperators are generally made of

Answer 6

silicon carbide.

Question 7

Hammers and railway rails are normally made of

Answer 7

high carbon steel

Question 8

Softness of silver can be converted into hardness by alloying it with small quantity of

Answer 8

copper & nickel

Question 9

The addition of antimony in tin-based alloys improves its

Answer 9

deformation resistance.

Question 10

The melleability of a material is the property by virtue of which it can be rolled or hammered into thin sheets. Which of the following materials has the miximum malleability ?

Lead
Copper
Aluminium
Wrought iron

Answer 10

Lead

Question 11

The main purpose of galvanising iron sheets is to

Answer 11

prevent the action of water.

Question 12

The impure iron (pig iron) that is tapped out from blast furnace contains about __________ percent carbon.

Answer 12

4

Question 13

Invar used in thermocouples is an alloy of nickel and

Answer 13

iron

Question 14

Lead pipes are not safe for carrying drinking water because water containing dissolved oxygen attacks lead thereby forming poisonous Pb (OH)2. Lead pipes are readily corroded by

Answer 14

acetic acid

Question 15

Constituents of stellite are

Answer 15

cobalt, chromium and tungsten.

Question 16

Residual magnetism in steel for magnets is increased by the addition of

Answer 16

cobalt

Question 17

Presence of nickel in steel improves its

Answer 17

corrosion resistance.

Question 18

Cementite is

Fe3C chemically.

a compound of carbon and iron.

characterised by an orthorhombic crystal structure.

all (a), (b) and (c).

Answer 18

all (a), (b) and (c).

Question 19

Acetylene gas holder is made of

Answer 19

steel

Question 20

Sulphur melting pit in the sulphuric acid plant is made of

Answer 20

steel or cement-brick lined.

Question 21

The hardest material just prior to diamond in Mho’s scale is

Answer 21

corrundum

Question 22

Percentage elongation of a material is a measure of its

Answer 22

ductility

Question 23

Chlorination of benzene is done to produce benzene hexachloride (a pesticide) in a photochemical reactor lined with

Answer 23

lead or glass

Question 24

Heavy duty bearings are usually made of

Answer 24

white metal

Question 25

Dielectric strength of a material is

Answer 25

its capacity to withstand high voltage.

Question 26

Which of the following stainless steels is non-magnetic ?

Answer 26

Austenitic

Question 27

18-4-1 high speed steel contains 18%, 4% and 1% respectively of

Answer 27

tungsten, chromium and vanadium

Question 28

Aluminum as a material of construction suffers from the disadvantage of

Answer 28

rather low tensile strength.

Question 29

Babbit metal used for bearings is a____base alloy.

Answer 29

tin

Question 30

Cast iron has very high

Answer 30

compressive strength

Question 31

Liquid ammonia is shipped in __________ containers.

Answer 31

glass

Question 32

Cermets are __________ materials.

Answer 32

refractory

Question 33

Cast irons are generally specified by their

Answer 33

tensile strength

Question 34

Austenitic manganese steel used for making jaws of crushing machines contains about __________ percent manganese.

Answer 34

12-14

Question 35

White cast iron is not

Answer 35

malleable

Question 36

Galvanised iron is

Answer 36

protected from rusting

Question 37

German silver used for decorative purposes contains maximum percentage of silver

Answer 37

copper

Question 38

The metals occuring at the lower most position in the electromotive series

Answer 38

resist corrosion very strongly.

Question 39

German silver in an alloy of

Answer 39

copper, nickel and zinc.

Question 40

A suitable material of construction to use with fuming sulphuric acid is

Answer 40

monel

Question 41

Which of the following crystal structures characterises the austenitic stainless steel?

Answer 41

Face centred cubic

Question 42

Caustic soda is produced in a mercury cell having anode and cathode made respectively of moving mercury and

Answer 42

graphite and moving mercury.

Question 43

Addition of __________ in steel can help in increasing the depth of hardness.

Answer 43

tungsten

Question 44

Which of the following has the highest compressive strength ?

Answer 44

High carbon steel

Question 45

Zinc is not used

Answer 45

as an alloying element in various bronzes.

Question 46

Refined acetic acid storage vessel are made of

Answer 46

Aluminum

Question 47

Addition of __________ to the steel helps in increasing the residual magnetism in steel used for making magnets.

Answer 47

cobalt

Question 48

Constantan is an alloy of

Answer 48

Cu (55%) & Ni (45%).