21. Galvanising (i.e., zinc coating) of steel sheets is done to
Prevent its rusting by contact with corrosive atmosphere
Protect the base metal by cathodic protection
Both A & B
Neither A nor B
✅ The correct answer is option C.
Materials and Construction MCQs
22. Steel balls for ball bearings are generally made of __________ steel.
Cast
Stainless
Free carbon
Carbon chrome
✅ The correct answer is option D.
23. Which of the following will have the highest melting point?
Pig iron
Mild steel
Wrought iron
High carbon steel
✅ The correct answer is option C.
24. __________ moulding process can not be used for thermoplastic plastics.
Compression
Extrusion
Injection
None of these
✅ The correct answer is option C.
25. Nickel is a __________ material.
Ferromagnetic
Diamagnetic
Paramagnetic
None of these
✅ The correct answer is option A.
26. Cast iron vessels are not suitable for the storage of
Freon
H₂SO₄ (95%) at room temperature
H₂SO₄ (fuming)
Wet SO₂
✅ The correct answer is option D.
27. Cast iron is a __________ material.
Brittle
Ductile
Tough
Malleable
✅ The correct answer is option A.
28. The heat treatment process to which castings and the steel balls produced by cold heading are subjected is
Tempering
Normalising
Annealing
None of these
✅ The correct answer is option B.
29. How many atoms are there per unit cell in a body centred cubic lattice system?
2
3
4
6
✅ The correct answer is option A.
30. Phenol is not shipped in
Nickel lined steel tank cars
Galvanised or tin lined drums
Boxed glass carboys
Cast iron containers
✅ The correct answer is option D.