669. During decarburising of a plain carbon steel, the thickness of ferrite layer growth is proportional to
A. Time
B. Square root of time
C. Square of time
D. Cube of time
✅ The correct answer is option B.
671. A psychrometer does not measure the __________ temperature of moist air.
A. Dew point
B. Dry bulb
C. Wet bulb
D. None of these
✅ The correct answer is option A.
673. __________ of hard alloy and tool steel is done to make it easily machinable.
A. Case carburising
B. Tempering
C. Normalising
D. Annealing
✅ The correct answer is option B.
676. The life of a ball bearing is inversely proportional to
A. (load)1
B. (load)2
C. (load)3
D. (load)0.33
✅ The correct answer is option C.
679. Strain hardening effect in metals subjected to cold working is due to the __________ mechanism.
A. Slip
B. Fracture
C. Winning
D. Dislocation
✅ The correct answer is option D.
682. Holes in a plate for rivetted joints is preferably made by
A. Drilling
B. Tapping
C. Reaming
D. Punching
✅ The correct answer is option A.
685. Carnot cycle is also termed as the constant __________ cycle in thermodynamics.
A. Entropy
B. Pressure
C. Volume
D. Heat
✅ The correct answer is option D.
688. Which of the following is an inedible oil ?
A. Corn oil
B. Tallow oil
C. Olive oil
D. Cotton seed oil
✅ The correct answer is option B.
691. With increase in carbon percentage in steel, its
A. Yield stress decreases
B. Elongation percent increases
C. Tensile strength increases
D. Impact strength increases
✅ The correct answer is option C.
656. Number of electrons in the outermost shell of a semi-conductor material is
A. 2
B. 4
C. 6
D. 8
✅ The correct answer is option D.