839. The hardness of a grinding wheel is specified by the
A. Alphabetical letter
B. Rockwell hardness number
C. Brinell hardness number
D. None of these
✅ The correct answer is option A.
841. Which of the following materials has the maximum shrinkage allowance ?
A. Brass
B. Cast iron
C. Lead
D. Aluminium alloy
✅ The correct answer is option C.
843. Out of the following, the lowest packing of atoms exists in __________ crystal lattice structure.
A. Hexagonal close, packed (hcp)
B. Face centred cubic (fcc)
C. Body centred cubic (bcc)
D. Simple cubic
✅ The correct answer is option D.
845. Material of construction of surveying metallic tapes is __________ which has low coefficient of expansion & enough strength.
A. Constantan
B. Invar
C. Pewter metal
D. Monel metal
✅ The correct answer is option B.
848. To counteract the bad effects of strain hardening on a cold formed part, it must be
A. Tempered
B. Normalised
C. Annealed
D. Hardened
✅ The correct answer is option C.
851. Electrochemical corrosion occurs
A. Where the liquid electrolytes containing free ions are present
B. Only in alloys
C. Only in pure metals
D. Due to direct chemical action of metal with oxygen
✅ The correct answer is option A.
854. Oxyacetylene reducing flame is used while carrying out welding on
A. Alloy steel
B. Grey cast iron
C. Mild steel
D. High carbon steel
✅ The correct answer is option C.
818. Pipelines carrying various utilities in chemical industries are identified by their colour codes. The color of pipeline carrying steam is
A. Black
B. Silver grey
C. Green
D. Yellow
✅ The correct answer is option B.
821. Saturated steam at a pressure of 25 kg/cm² is throttled to attain 5 kg/cm² . Then the outcoming steam will be
A. Wet
B. Saturated
C. Superheated
D. None of these
✅ The correct answer is option C.
824. Nitriding of steel is a process for
A. Case hardening
B. Spheroidising
C. Normalising
D. Annealing
✅ The correct answer is option A.