What is the effect on the performance of the economiser in the thermal power plant boiler, if the feed water temperature is very low due to preheaters being out for repairs or starving of steam supply ?
Betweenand 370°C, blue brittleness is caused in mild steel because of the
Which of the following metals occurs in nature in their free metallic state ?
The most suitable material for a sewer for carrying storm water is
Which of the following metals can be extracted from its ore by both pyrometallur-gical as well as hydrometallurgical methods ?
Minimum number of members required to form a Public Limited Joint Stock Com-pany is
In 18-4-1 high speed steel,4 & 1 respectively denote the percentage of
The joint for soldering is supported by binding wire made of
Which of the following has rotten eggy smell ?
Lead is most readily dissolved in
The only suitable method for hardening the low carbon steel is case hardening. Which of the following is a case hardening process?
Brass parts with high residual tensile stress at the surface are susceptible to season cracking (i.e. spontaneous cracking occuring on exposure to atmospheric corrosion), if its zinc percentage is more than
The velocity of sound in air is independent of changes in its
Which of the following materials has the maximum shrinkage allowance ?
Corona discharge is related to the operation of a/an
Window panes of aeroplanes are normally made of
Material of construction of foundary crucible is
Brittleness induced due to the presence of sulphur in steel can be reduced by adding
Fatigue strength of a metal is improved by
Which of the following hardness tests uses the depth of penetration caused by the indentor as the parameter for arriving at the hardness value of a material ?
Aluminium oxide (an abrasive) is used for grinding
In a totally irreversible isothermal expansion process for an ideal gas, ΔE =ΔH =Then ΔQ and ΔS will be
The magnitude of water hammer caused in pipe flow is independent of the
Sewage is not an excellent medium for the growth of
If a heat transfer surface is pock-marked with a number of cavities, then as compared to a smooth surface the heat transfer by __________ will not increase.
In an eutectic system, two elements are completely
Tempering of a material does not improve its
Role of a "collector" in froth floatation is to
The hardenability of steel decreases with
The main reducing agent in iron blast furnace is
Freezing ofoleum during its shipment in winter is avoided by the addition of small amount of
Which of the following is a synthetic abrasive ?
Annealing of cast iron
Water flow in the river during flood can be categorised as the __________ flow.
Vibration uptokilo hertz can be most accurately measured by a __________ type accelerometer.
Plastics as a material of construction suffer from the drawback of low
Out of the following, the best material capable of withstanding shock & vibration without the danger of cracking is
__________ flux is used for the extraction of metal from its self fluxing ores.
Saturated steam at a pressure ofkg/cm2 is throttled to attain 5 kg/cm2 . Then the outcoming steam will be
The most commonly used moderator in nuclear power plant is
In a casting, cold shut defect is caused by
Sulphur is melted in the sulphuric acid plant most commonly by employing
A metalloid possesses the characteristics of both the metals and non-metals. Which of the following is not a metalloid ?
Which of the following pair is correctly matched?
Half life of a radioactive isotope corresponds to the time required for half of the __________ to decay.
Piezoelectric is a material
Oxygen content below __________ percent in air contaminated with nitrogen does not support combustion and is unsafe for humane exposure.
Which of the following is a boiler accessory i.e., not a boiler mounting ?
The instrument based on the following principle is used for the measurement of oxygen only in the flue gases.
Toughness of a material is measured by the
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