MCQ
1. Iron is--
paramagnetic
fermelectric
ferromagnetic
dielectric
2. The material mixed before ore is subjected for smelting in the extraction of iron are-
Coke and Silica
Coke and limestone
Limestone and silica
Coke, limestone and silica
3. The percentage of carbon in cast iron varies from--
0.1 to 0.5
1 to 1.7
5 to 1
1.7 to 4.5
4. Ferromagnetic alpha iron exists in temperature range of--
below 723°C
770-910°C
910-1440°C
1400-1539°C
5. Chilled cast iron has--
no graphite
a very high percentage of graphite
a low percentage of graphite
graphite as its basic constituent of composition
6. Pure iron is the structure of--.
ferrite
anstenite
ferrite and cementite
pearlite
7. Pearlite is combination of 87% ferrite and13% cemented-
yes
no
8. The metallic structure of mild steel is-
body centred cubic
face centred cubic
hexagonal close packed
cubic structure
9. Carbon steel is--
made by adding carbon in steel
refined from cast iron
an alloy of iron and carbon with varying quantities of phosphorus and sulphur
extensively used for making cutting tools
10. The following element can't impart high strength at elevated temperature—
manganese
nickel
magnesium
silicon
11. A reversible change in the atomic structure of the steel with a corresponding change in the properties is known as--
allotropic change
heat treatment
recrystallisation
precipitation
12. The crystal structure of gamma iron is—
body centred cubic
face centred cubic
hexagonal close packed
cubic structure
13. A reversible change in the atomic structure of steel with corresponding change in the properties is known as—
molecular change
physical change
allotropic change
solidus change
14. Paramagnetic alpha iron changes to gamma iron at--
770°C
910°C
1440°C
1539°C
15. The crystal of alpha iron is-
body centred cubic
face centred cubic
hexagonal close packed
cubic structure
16. The unique property of cast iron is its high--
malleability
ductility
surface finish
damping characteristics
17. The temperature at which ferromagnetic alpha iron transforms to paramagnetic alpha iron is-
770°C
910°C
1050°C
below recrystallisation temperature
18. Gamma iron exits at following temperature--.
room temperature
between 1400°C and 1539°C
near melting point
between 910°C and 1400°C
19. 'Killed steels are those steels—
which are destroyed by burning
which after their destruction are recycled to produce fresh steel
which are deoxidised in the ladle with silicon and aluminium
in which carbon is compictely burnt
20. The molecules in a solid move—
in a random manner
in a haphazard way
in circular motion
back and forth like tiny pendulums