Description : Glass is - (1) Super cooled liquid (2) Crystalline solid (3) Liquid crystal (4) None of these
Last Answer : (1) Super cooled liquid Explanation: Glass is sometimes called a Super cooled liquid because it does not form a crystalline structure, but instead forms an amorphous solid that allows molecules in the material to continue to move.
Description : Which of the following is a super-cooled liquid? (1) Ice-cream (2) Ammonia (3) Glass (4) Wood
Last Answer : (3) Glass Explanation: Glass is considered to be a supercooled liquid due to its lack of a first-order phase transition where certain thermodynamic variables such as volume, entropy ... where the intensive thermodynamic variables such as the thermal expansivity and heat capacity are discontinuous.
Description : Why is glass referred to as ‘Super Cooled liquid’?
Last Answer : The molecules of glass are arranged as in that of a liquid. On heating, glass first becomes soft and flows like a liquid. It does not have a definite melting point. Hence glass is referred to as super cooled liquid.
Last Answer : Glass
Description : Generally __________ are subjected to galvanising (i.e., zinc coating). (A) Non-ferrous metals (B) Non-metals (C) Low carbon steels (D) Stainless steel
Last Answer : (C) Low carbon steels
Description : Cement mainly contains (A) CaO, SiO2 , Al2O3 (B) MgO, SiO2 , K2O (C) Al2O3 , MgO, Fe2O3 (D) CaO, MgO, K2O
Last Answer : (A) CaO, SiO2 , Al2O3
Description : Portland cement consists mainly of (A) CaO & SiO2 (B) SiO2 & Al2O3 (C) CaO & Al2O3 (D) CaO & Fe2O3
Last Answer : (A) CaO & SiO2
Description : A super cooled liquid?
Description : Co-efficient of thermal expansion of glass is decreased by the addition of __________ during its manufacture. (A) CaO (B) MnO2 (C) ZnO (D) FeS
Last Answer : (C) ZnO
Description : Pick out the wrong statement. (A) Hard glass which is used for making laboratory glass wares is a mixture of sodium borosilicate and aluminium borosilicate (B) Glass is decolorized during its manufacture by ... Na2O . CaO . 6SiO2 (D) Red color is imparted to glass by addition of arsenic oxide
Last Answer : (D) Red color is imparted to glass by addition of arsenic oxide
Description : Blue colour is imparted to glass by the addition of (A) FeSO4 (B) PbO (C) CaO (D) NaOH
Last Answer : (C) CaO
Description : When a gas is subjected to adiabatic expansion, it gets cooled due to (A) Decrease in velocity (B) Decrease in temperature (C) Decrease in kinetic energy (D) Energy spent in doing work
Last Answer : (D) Energy spent in doing work
Description : Which raw material is used to impart colour to the glass? a) Al2O3 b) CoO c) CaO d) MgO
Last Answer : b) CoO
Description : Noise produced by cooling fans (employed in air cooled heat exchangers or cooling tower) is mainly caused due to the turbulence created by blade passage through air. It can be reduced by use of a slower fan (A) With greater ... (B) Of increased diameter (C) Both (A) & (B) (D) Neither (A) nor (B)
Last Answer : (C) Both (A) & (B)
Description : In case of a super-cooled solution, which is on the verge of crystallisation, the free energy of the solution as compared to that of the solid is (A) More (B) Less (C) Same (D) More or less; depends on the nature of solution
Last Answer : (A) More
Description : Maximum consumption of zinc is in (A) Alloying (B) Galvanising (C) Utensil manufacture (D) Electrical industr
Last Answer : (B) Galvanising
Description : The main purpose of galvanising iron sheets is to (A) Harden the surface (B) Increase its glossiness and lustre (C) Prevent the action of water (D) Prevent the action of oxygen
Last Answer : (C) Prevent the action of water
Description : Galvanising is not a zinc diffusion process. A zinc diffusion process istermed as (A) Sherardizing (B) Parkerising (C) Anodising (D) None of these
Last Answer : (A) Sherardizing
Description : Galvanising (i.e., zinc coating) of steel sheets is done to (A) Prevent its rusting by contact with corrosive atmosphere (B) Protect the base metal by cathodic protection (C) Both (A) & (B) (D) Neither (A) nor (B)
Description : The process of coating steel sheets by zinc to improve its corrosion resistance is called (A) Calorising (B) Galvanising (C) Zincification (D) Tempering
Description : Galvanising is generally done on (A) Non-ferrous metals (B) Low carbon steel (C) Stainless steel (D) Cast iron
Last Answer : (B) Low carbon steel
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 : Hot dipping process is used for coating a low melting point metal (e.g. Pb, Sn, Zn) on iron, steel & copper having relatively higher melting points. Which of the following is not a hot dipping process? (A) Galvanising (B) Tinning (C) Sherardizing (D) None of these
Last Answer : (C) Sherardizing
Description : Coating thickness in case of galvanising of steel sheet generally corresponds to the deposition of __________ gms of zinc per m2 of steel strip. (A) 5-10 (B) 1000-1500 (C) 120-500 (D) 1500-3000
Last Answer : Option C
Description : Which of the following reactors is operated at high neutron flux and low power level? (A) Breeder reactor (B) Research reactor (C) Heterogeneous reactor (D) Liquid metal (e.g., molten sodium) cooled reactor
Last Answer : (B) Research reactor
Description : Thorium can be converted into U-233 in a __________ reactor. (A) Liquid metal cooled (B) Fast breeder (C) Thermal (D) Swimming pool
Last Answer : (B) Fast breeder
Description : The type of pump used for the recirculation of molten sodium coolant in liquid metal cooled reactor is a/an __________ pump. (A) Electromagnetic (B) Reciprocating (C) Centrifugal (D) Volute
Last Answer : (A) Electromagnetic
Description : __________ is the temperature at which a gas-vapor mixture becomes saturated, when cooled at constant total pressure out of contact with a liquid. (A) Dew point (B) Bubble point (C) Dry bulb temperature (D) Wet bulb temperature
Last Answer : (A) Dew point
Description : Double pipe heat exchangers are preferably useful, when (A) High viscosity liquid is to be cooled (B) Requirement of heat transfer area is low (C) Overall heat transfer co-efficient is very high (D) A corrosive liquid is to be heated
Last Answer : (B) Requirement of heat transfer area is low
Description : In a gas-liquid shell and tube heat exchanger, the (A) Presence of a non-condensable gas decreases the condensing film coefficient (B) Gases under high pressure are routed through the tube side, because high pressure ... water or steam condensate remain localised to the tubes (D) All 'a', 'b' & 'c'
Last Answer : (D) All 'a', 'b' & 'c'
Description : Heat flux increases with temperature drop beyond the Leiden frost point in the plot of heat flux vs. temperature drop for a boiling liquid, because (A) Convection becomes important (B) Conduction becomes important (C) Radiation becomes important (D) Sub-cooled boiling occurs
Last Answer : (C) Radiation becomes important
Description : In sub-cooled boiling, (A) Temperature of the heating surface is less than the boiling point of the liquid (B) Temperature of the heating surface is more than the boiling point of the liquid (C) ... from heating surface are absorbed by the mass of the liquid (D) Very large vapour space is necessary
Last Answer : (B) Temperature of the heating surface is more than the boiling point of the liquid
Description : Which of the following situations can be approximated to a steady state heat transfer system? (A) A red hot steel slab (having outside surface temperature as 1300°C) exposed to the atmospheric air at ... flowing at the rate of 6 Kg/minute through a copper pipe exposed to atmospheric air at 35°C
Last Answer : (B) 10 kg of dry saturated steam at 8 kgf/cm2 flowing through a short length of stainless steel pipe exposed to atmospheric air at 35°C
Description : A liquid under pressure greater than its vapour pressure for the temperature involved is called a __________ liquid. (A) Sub-cooled (B) Saturated (C) Non-solidifiable (D) None of these
Last Answer : (A) Sub-cooled
Description : During manufacture of glass, molten glass is cooled slowly to make it
Last Answer : lose brittleness.
Description : Why does glass crack when suddenly heated or cooled?
Last Answer : Glass is a bad conductor of heat but expands easily on heating. When it is suddenly heated or cooled, due to rapid expansion and contraction along the hot region and cold region it begins to crack.
Description : Which of the following is false? (a) Mica is usually found in metamorphic and igneous rocks (b) Aluminium has the advantage over iron as it is resistant to corrosion (c) line is mostly used in galvanising iron and steel goods (d) Manganese is largely used in making fertilizers
Last Answer : Ans: (d)
Description : The coating of a thin layer of zinc on steel or iron objects is known as – (1) Hot dipping (2) Tinning (3) Galvanising (4) Electroplating
Last Answer : (3) Galvanising Explanation: Galvanization is the process of applying a protective zinc coating to steel or iron, in order to prevent rusting. Although galvanization can be done with electrochemical and ... is hot-dip galvanization, in which steel parts are submerged in a bath of molten zinc.
Description : What is galvanising?
Last Answer : Coating iron with Zinc
Description : Galvanising means covering iron with a thin coat of (A) Tin (B) Zinc (C) Glaze (D) Coal tar
Last Answer : Answer: Option B
Description : Write two points of similarity between sherardizing and galvanising process.
Last Answer : 1) Sherardizing and galvanizing are the processes of avoiding corrosion of metal. 2) Zinc is used as coating metal on iron base metal.
Description : The metal chiefly used for galvanising iron is : (1) Zinc (2) Mercury (3) Cadmium (4) Tin
Last Answer : Zinc
Description : The coating of a thin layer of zinc on steel or iron objects is known as (1) Hot dipping (2) Tinning (3) Galvanising (4) Electroplating
Last Answer : Galvanising
Description : Low grade phosphate rock can be used in electrical furnace, because (A) Of the better CaO/SiO2 balance for slag formation (B) CaO content is less (C) It is cheap (D) It produces low cost product
Last Answer : (A) Of the better CaO/SiO2 balance for slag formation
Description : Considering the endothermic dissociation of CaCO3 in a closed vessel (CaCO3 ⇌ CaO + CO2 ), the pressure of CO2 increases, if (A) A catalyst is added (B) The temperature is increased (C) An inert gas is pumped keeping the temperature constant (D) None of these
Last Answer : (B) The temperature is increased
Description : Calcination reaction of limestone (CaCO3 → CaO + CO2 ) goes to completion in the rotary kiln, because (A) CaO is not dissociated (B) CO2 escapes continuously (C) Of high calcination temperature (D) CaO is more stable than CaCO3
Last Answer : (B) CO2 escapes continuously
Description : In case of calcination of limestone, CaCO3 CaO + CO2 , the addition of more of CaO will result in __________ in the concentration of CO2 . (A) No change (B) Increase (C) Decrease (D) Unpredictable from the data
Last Answer : (A) No change
Description : CaO is called (A) Quick lime (B) Slaked lime (C) Limestone (D) Calcite
Last Answer : (A) Quick lime
Description : Pick out the endothermic reaction out of the following. (A) C+ ½O2 = CO (B) CO + 3H2 = CH4 + H2O (C) CaCO3 = CaO + CO2 (D) CO + ½O2 = CO2
Last Answer : (C) CaCO3 = CaO + CO2
Description : Which of the following is the second major component of cement? (A) Al2O3 (B) SiO2 (C) CaO (D) Fe2O3
Last Answer : (B) SiO2