In a neutral solution
A. H+ ions are absent
B. OH- ions are absent
C. Both H+ and OH- ions are present in very small but equal concentration
D. None of these
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In an isochoric process,
A. There is no transfer of mass and energy
B. Free expansion of an ideal gas occurs
C. No mechanical work is done by the system
D. All of the above
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The passage between the nozzle and the __________ is called 'sprue' in case of injection moulding.
A. Runner
B. Cylinder
C. Mold
D. None of these
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Heat dissipation in cooling towers is mainly by
A. Conduction
B. Convection
C. Evaporation
D. Radiation
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Yield strength of a polycrystalline metal with an average grain size d, is proportional to
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Presence of sulphur in the fuel fired in a furnace
A. Contributes to its heating value
B. Helps in electrostatic precipitation of ash from flue gases
C. Corrodes ducts & air preheater, if the flue gas temperature is low
D. All of the above
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__________ furnace is generally used in the non-ferrous foundaries.
A. Direct arc
B. Indirect arc
C. Resistance
D. Induction
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Which of the following metals occurs in nature in their free metallic state?
A. Au & Ag
B. Pb & Zn
C. Cu & Ni
D. None of these
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Steels with high carbon equivalent have poor weldability, because in these steels during welding
A. Carbon and other alloying elements get oxidised from the weld pool
B. Excessive ferrite forms in the heat affected zone leading to poor toughness of the weld
C. Martensite forms in the heat affected zone leading to poor toughness/ductility of the weld
D. Segregation of carbon and other element occurs in the weld pool leading to poor properties of the weld
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In a counter flow heat exchanger, hot fluid enters at 170°C & leaves at 150°C, while the cold fluid enters at 50°C & leaves at 70°C. The arithmetic mean temperature difference in this case is __________ °C.
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Dislocation cross-slip is difficult in those materials, which have
A. Large number of slip systems
B. High work hardening rate
C. Coarse grain size
D. Low stacking fault energy
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The most economical channel section for the fluid flow is the one for which the discharge is maximum for a given cross-sectional area. Vertical velocity distribution in an open channel for laminar flow can be assumed to be
A. Parabolic
B. Hyperbolic
C. Straight line
D. None of these
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__________ the exhaust gas is an indication of the incomplete combustion of fuel.
A. Low temperature of
B. High temperature of
C. High % of CO in
D. High % of CO2 in
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The softness or hardness of a grinding wheel depends upon the type & amount of bonding material used. For general purpose cutter grinding __________ grinding wheel is normally used.
A. Hard
B. Soft
C. Silicon carbide
D. Aluminium oxide
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Glycerene is used as a coolant in cooling of some engines instead of water, because
A. Its higher boiling point (290°C) increases its heat carrying capacity
B. Compartively less weight of coolant is required
C. Smaller radiator can be used
D. All of the above
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For the running of power generating turbines, the steam used should be
A. Wet
B. Superheated
C. At ordinary pressure
D. None of these
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The material used for coating the welding electrode is termed as the
A. Flux
B. Slag
C. Protective layer
D. Binder
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Drossing is a __________ operation.
A. Smelting
B. Dressing
C. Roasting
D. None of the above
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Grinding wheel made of silicon carbide is most suitable for grinding materials of low tensile strength (e.g; tough bronze). Grinding is a __________ operation.
A. Turning
B. Dressing
C. Forming
D. Surface finishing
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In an amorphous material, atoms defy any definite atomic structure and exist in random pattern just like in liquid. Which of the following is an amorphous material?
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