711. Transformation range for ferrous material is the temperature interval during which __________ is formed during its heating.
A. Cementite
B. Austenite
C. Martensite
D. Pearlite
✅ The correct answer is option B.
713. Slight displacement of a floating body in liquid makes it to oscillate about its
A. Centre of pressure
B. Centre of gravity
C. Metacentre
D. Centre of pressure
✅ The correct answer is option C.
715. __________ flux is used for the extraction of metal from its self fluxing ores.
A. No
B. Acid
C. Basic
D. Neutral
✅ The correct answer is option A.
717. While the recrystallisation temperature for pure metals is 0.3 Tm, the same for alloys is equal to __________ x Tm (where, Tm Melting temperature).
A. 0.25
B. 0.45
C. 0.70
D. 0.95
✅ The correct answer is option C.
719. Reynolds number of a fluid flowing in a circular pipe is 10000. What will be the Reynolds number when the fluid velocity is decreased by 30% & the pipe diameter is increased by 30% ?
A. 9100
B. 13000
C. 7000
D. 2550
✅ The correct answer is option A.
721. Reduction reaction involves the
A. Loss of electrons
B. Increase in oxidation number
C. Gain of electrons
D. Addition of oxygen
✅ The correct answer is option C.
723. The main reducing agent in iron blast furnace is
A. Carbon dioxide
B. Carbon monoxide
C. Oxygen
D. Air
✅ The correct answer is option B.
726. The ‘transition temperature’ for ductile to brittle behaviour of steel increases with increase in the __________ content in steel.
A. Carbon
B. Manganese
C. Both A & B
D. Neither A nor B
✅ The correct answer is option A.
729. Dowtherm is a
A. High temperature heating medium (a petroleum product)
B. Product of coal tar distillation
C. Very heat sensitive material
D. None of these
✅ The correct answer is option A.
732. Hot & cold working of material causes its __________ deformation.
A. Visco-elastic
B. Isotropic
C. Elastic
D. Plastic
✅ The correct answer is option D.