Refractory bricks burnt at very high temperature have got
(A) Greater resistance to corrosion by slags
(B) Less resistance to corrosion by slags
(C) High spalling tendency
(D) None of these

1 Answer

Answer :

(A) Greater resistance to corrosion by slags

Related questions

Description : Resistance to fusion of the refractory under a steady rising temperature condition is called (A) Spalling (B) Refractoriness (C) Both (A) & (B) (D) Neither (A) nor (B)

Last Answer : (B) Refractoriness

Description : Which of the following bricks are used for lining of furnaces? (A) Over-burnt bricks (B) Under-burnt bricks (C) Refractory bricks (D) First class bricks

Last Answer : Answer: Option C

Description : Highly porous refractory bricks are (A) Less susceptible to chemical attack by molten fluxes and gases etc (B) Very strong (C) Having very high thermal conductivity (D) None of these

Last Answer : (D) None of these

Description : Refractory bricks resist (A) High temperature (B) Chemical action (C) Dampness (D) All the above

Last Answer : Answer: Option A

Description : Rotary driers are generally made of (A) Cast iron (B) Mild steel (C) High silicon iron (14% Si) (D) Tin lined with refractory bricks

Last Answer : (B) Mild steel

Description : Refractory bricks having high thermal conductivity is desirable, when it is to be used in the (A) L.D. converter (B) Blast furnace (C) Rotary kiln (D) Recuperator

Last Answer : (D) Recuperator

Description : Pick up the correct statement from the following: (A) The baked earth is called terra-cotta (B) The articles prepared from clay which is burnt at low temperature and cooled down slowly, are called ... clays which as mixed with stone and crushed pottery, are called stone ware (D) All the above

Last Answer : Answer: Option D

Description : Sulphuric acid is mixed with ground phosphate rock (to produce phosphoric acid) in a steel digestor lined with (A) Acidic refractory (B) Rubber (C) Karbate (D) Lead or acid proof bricks

Last Answer : (A) Acidic refractory

Description : Sulphuric acid is mixed with ground phosphate rock (to produce phosphoric acid) in a steel digestor lined with (A) Acidic refractory (B) Rubber (C) Karbate (D) Lead or acid-proof bricks

Last Answer : (D) Lead or acid-proof bricks

Description : Refractory bricks are usually dried in a __________ dryer. (A) Tray (B) Tunnel (C) Conveyor (D) Festoon

Last Answer : (B) Tunnel

Description : Absorptivity of a perfect black body is unity. Which of the following has maximum absorptivity? (A) Aluminium foil (B) Refractory bricks (C) Iron plate (D) Coke breeze

Last Answer : (D) Coke breeze

Description : Which of the following has the minimum absorptivity? (A) Aluminium foil (B) Coal dust (C) Refractory bricks (D) Iron plates

Last Answer : (A) Aluminium foil

Description : Which of the following is the most widely used heat insulating material for pipelines carrying steam? (A) Tar dolomite bricks followed by asbestos (B) Fireclay refractory followed by aluminium sheet (C) Cotton followed by aluminium foil (D) 85% magnesia cement and glass wool

Last Answer : (D) 85% magnesia cement and glass wool

Description : Large tonnage of refractory bricks are dried in a (A) Shaft furnace (B) Rotary hearth furnace (C) Tunnel kiln (D) Muffle furnace

Last Answer : (C) Tunnel kiln

Description : Pot furnace which is either regenerative or recuperative, is used in the manufacture of (A) Glass (B) Stainless steel (C) Potteries (D) Refractory bricks

Last Answer : (A) Glass

Description : Refractory bricks are used for (A) Retaining walls (B) Columns (C) Piers (D) Combustion chambers

Last Answer : Answer: Option D

Description : Refractory bricks are (A) Neutral refractory bricks (B) Acid refractory bricks (C) Basic refractory bricks (D) All the above

Last Answer : Answer: Option D

Description : Size reduction of the __________ can be suitably done by ball mills, crushing rolls and rod mills. (A) Metalliferous ores (B) Non-metallic ores (C) Basic slags (D) Asbestos & mica

Last Answer : (A) Metalliferous ores

Description : Jhumb bricks are (A) Under burnt (B) Over burnt (C) Kutcha (D) None of these

Last Answer : Answer: Option B

Description : Second class bricks (A) Are of dark brown colour (B) Produce a metallic sound when struck (C) Are well burnt (D) Are under burnt

Last Answer : Answer: Option B

Description : What are the various operations involved in manufacturing of burnt clay bricks? 

Last Answer : Manufacturing of Burnt Clay Brick consists of a) Preparation of clay. b) Moulding c) Drying d) Burning.

Description : Classify burnt clay bricks.

Last Answer : The bricks used in the construction works are burnt bricks and they are classified into the following four categories: 1) First class bricks 2) Second class bricks 3) Third class bricks 4 ... a compact structure and hence they are sometimes found to be stronger than even the first class bricks.

Description : Pick out the wrong statement regarding the solubility characteristics of high polymers. (A) Greater the degree of cross-linking in the polymer, lesser is its solubility (B) Polymers having more ... of the solvent (D) High molecular weight polymers on dissolving gives solution of very low viscosity

Last Answer : (D) High molecular weight polymers on dissolving gives solution of very low viscosity

Description : Mineral oils (e.g. petroleum oils) are preferred over fatty oils (e.g. mustard oil, ghee, tallow, palm oil, olive oil etc.) as a lubricant due to its (A) Poor oxidation stability and high gum forming ... at elevated temperature (C) Hydrolysis tendency in presence of water (D) All (A), (B) and (C)

Last Answer : (D) All (A), (B) and (C)

Description : Wrought iron is having very high (A) Hardness (B) Strength (C) Corrosion resistance (D) Susceptibility to changes in its properties by heat treatment

Last Answer : (C) Corrosion resistance

Description : Pick out the wrong statement. (A) Pulverised fuel can be completely burnt with less percentage of excess air compared to lump coal (B) Low grade coal can be used, but generally high volatile ... and atmosphere (oxidising or reducing) is easily possible with pulverised fuel firing (D) None of these

Last Answer : (D) None of these

Description : The removal of paint from electrical equipment, such as generators, should be cautiously undertaken because ____________. A. the mechanical shock of paint removal lessens the dielectric strength ... phase windings frequently become isolated from each other due to dust interference at the terminals

Last Answer : Answer: B

Description : Pitch (a product of coal tar distillation) is always mixed with creosote oil, when it is to be burnt in a burner, because (A) Its calorific value is very less (B) Tar neutralises the residual acids ... for its transportation through pipelines at economic pressure drop (D) All (A), (B) and (C)

Last Answer : (C) It reduces viscosity and imparts fluidity for its transportation through pipelines at economic pressure drop

Description : Spalling hammer is used for (A) Driving wooden headed chisels (B) Rough dressing of stones (C) Carving of stones (D) Breaking small projection of stones

Last Answer : Answer: Option B

Description : Ceramic nuclear metals compared to solid nuclear metals have (A) Higher melting points (B) Low strength at high temperature (C) More chances of radiation damage (D) Poorer corrosion resistance

Last Answer : (A) Higher melting points

Description : Aluminium alloy is one of the most suitable materials of construction for aircrafts mainly due to its (A) High strength to weight ratio (B) Low temperature strength properties (C) Its ability ... rolled, forged & stamped (D) High strength and corrosion & oxidation-resistance at elevated temperature

Last Answer : (A) High strength to weight ratio

Description : Choose the incorrect statement from the following: (a) The nuclear becomes weak if the nucleus contains too many protons compared to the number of neutrons (b) The nuclear force becomes weak if the ... (d) The nuclear force becomes very strong if the nucleus contains a large number of nucleons.

Last Answer : Ans:(d)

Description : The maximum adiabatic flame temperature is attained, when the fuel is burnt with (A) Theoretically required amount of air (B) More than theoretically required amount of air (C) Less than theoretically required amount of air (D) Theoretically required amount of oxygen

Last Answer : (D) Theoretically required amount of oxygen

Description : Ferric stainless steels compared to austenitic stainless steels (A) Have lower corrosion resistance (B) Are harder to fabricate (C) Are less ductile and hence less suitable for cold pressing (D) All (A), (B) and (C)

Last Answer : (D) All (A), (B) and (C)

Description : In a shell and tube heat exchanger, floating head is used for (A) Large temperature differentials (B) High heat transfer co-efficient (C) Low pressure drop (D) Less corrosion of tubes

Last Answer : (A) Large temperature differentials

Description : Test specimen for determination of refractoriness under load (RUL) of a refractory is heated in a (A) Furnace employing neutral atmosphere (B) Carbon resistance furnace (C) Reducing atmosphere (D) Furnace employing negative pressure

Last Answer : (B) Carbon resistance furnace

Description : __________ is the process of coating the surface of steel with aluminium oxide, thereby imparting it increased resistance to corrosion & oxidation upto a temperature of 700°C. (A) Veneering (B) Galvanising (C) Electroplating (D) Calorising

Last Answer : (D) Calorising

Description : Identify the false statement (A) Martensitic steels are less susceptible to pitting corrosion than austenitic steels (B) Pitting corrosion is usually very localised (C) Hydrogen embrittlement is facilitated by tensile stress (D) Stress corrosion cracking is facilitated by tensile stress

Last Answer : (A) Martensitic steels are less susceptible to pitting corrosion than austenitic steels

Description : Which of the following has a very high carbide forming tendency in steels? (A) Silicon (B) Chromium (C) Nickel (D) Vanadium

Last Answer : (D) Vanadium

Description : Coarse grained steels have (A) Low toughness (B) No tendency to distort (C) High density (D) Very high toughness

Last Answer : (B) No tendency to distort

Description : Wrought iron is (A) High carbon iron (B) Highly resistance to acid corrosion (C) Malleable & ductile; and hence is used for chain links, hooks & couplings (D) An alloy of iron, chromium & carbon

Last Answer : (C) Malleable & ductile; and hence is used for chain links, hooks & couplings

Description : Brass tubes are used in the manufacture of tubes of evaporators used in sugar and salt industries, mainly because of its (A) High co-efficient of thermal expansion (B) Low thermal conductivity (C) High corrosion resistance (D) All (A), (B) and (C)

Last Answer : (C) High corrosion resistance

Description : Wrought iron does not have (A) Uniform strength in all directions (B) Ability to hold protective coating (C) High ductility & corrosion resistance (D) Easily weldable characteristics

Last Answer : Option A

Description : The internal size of mould used in brick preparation is (A) Equal to the size of a fully burnt brick (B) Smaller than the size of a fully burnt brick (C) Greater than the size of a fully burnt brick (D) None of the above

Last Answer : Answer: Option C

Description : Heat transfer rate to the charge/stock in a furnace does not depend upon the (A) Type of fuels viz. solid, liquid or gaseous (B) Flue gas temperature (C) Emissivity of refractory walls (D) Initial temperature of the charged stock

Last Answer : (A) Type of fuels viz. solid, liquid or gaseous

Description : A furnace is made of a refractory brick wall of thickness 0.5 metre and thermal conductivity 0.7 W/m.°K For the same temperature drop and heat loss, this refractory wall can be replaced by a layer of diatomaceous earth of ... and thickness __________ metre. (A) 0.01 (B) 0.1 (C) 0.25 (D) 0.5

Last Answer : (B) 0.1

Description : Mild steel is (A) A low carbon steel (0.05 to 0.3% carbon) (B) Highly resistant to corrosion (as much as stainless steel) (C) A high carbon steel (0.5 to 1.5% carbon) (D) Very poor in strength & ductility

Last Answer : (A) A low carbon steel (0.05 to 0.3% carbon)

Description : High content copper amalgam . . . a. generally requires greater energy to accomplish trituration b. should be placed rapidly in large increments c. Continues to leak since the ... not cause galvanism in oral environment e. is equally effective as conventional alloys in clinical studies

Last Answer : a. generally requires greater energy to accomplish trituration

Description : A fuel containing carbon and carbon monoxide (but containing no hydrogen or its compounds) is burnt in pure oxygen at constant pressure. Its gross calorific value as compared to net calorific value will be (A) More (B) Less (C) Same (D) Data insufficient; can't be predicted

Last Answer : (C) Same