2122. Acetylene gas holder is made of
Copper
Cast iron
Steel
Monel metal
✅ The correct answer is option C.
2125. Liners of a ball mill are never made of
Lead
Alloy steel
Rubber or ceramic material
Cast iron
✅ The correct answer is option A.
2128. Wood is corroded by
Hydrochloric acid
SO₂ (dry or wet)
Chlorine (dry or wet)
All of the above
✅ The correct answer is option D.
2131. 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)?
Invar
Constantan
Chromel
Alumel
✅ The correct answer is option A.
2134. Wrought iron is
High carbon iron
Highly resistance to acid corrosion
Malleable & ductile; and hence is used for chain links, hooks & couplings
An alloy of iron, chromium & carbon
✅ The correct answer is option C.
2137. All materials obey Hooke’s law within elastic limit. When elastic limit is reached, the tensile strain
Increases very quickly
Decreases very quickly
Increases in proportion to stress
Decreases in proportion to stress
✅ The correct answer is option A.
2140. Iron rust is
Ferrous oxide
Hydrated ferric oxide
Powdered iron
Ferric sulphide
✅ The correct answer is option B.
2143. To improve the machinability of steel, it is generally subjected to
Spheroidising
Tempering
Normalising
Annealing
✅ The correct answer is option A.
2105. __________ possesses viscoelastic properties.
Cork
Glass
Graphite
Rubber
✅ The correct answer is option D.
2107. Which of the following is the softest material?
Quartz
Calcite
Corrundum
Flourite
✅ The correct answer is option B.