Description : Dittus-Boelter equation cannot be used for molten metals mainly due to its very low (A) Prandtl number (B) Grashoff number (C) Thermal conductivity (D) Viscosity
Last Answer : (A) Prandtl number
Description : Which of the following is not used as a medium for high temperature heating ? (A) Dowtherm (B) Mercury (C) Liquid metal (e.g. molten sodium) (D) Fused salts (e.g., an eutectic mixture of 53% KNO3 , 40% NaNO2and 7% NaNO3 )
Last Answer : (B) Mercury
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 : Which of the following statements about the physical properties of metal is not correct? (a) All metals are solid except mercury (b) Most metals are hard except sodium and potassium (c) Metals are not malleable (d) Most metals are ductile
Last Answer : Ans:(c)
Description : Choose a statement that correctly defines the term AMALGAM: A. Amalgam is a metallic powder composed of silver, tin, copper and zinc B. Amalgam is an alloy of two or more metals that have been dissolved in ... is mixed with mercury E. Amalgam is an alloy of two or more metals, one of them is tin
Last Answer : C. Amalgam is an alloy of two or more metals, one of them is mercury
Description : Which is the most commonly used molten metal for cooling of nuclear reactors? (A) Calcium (B) Sodium (C) Mercury (D) Zinc
Last Answer : (B) Sodium
Description : The metals commonly used for electroplating are – (1) Gold, Sodium and Chromium (2) Chromium, Copper and Nickel (3) Nickel, Lead and Chromium (4) Gold, Sodium and Potassium
Last Answer : (2) Chromium, Copper and Nickel Explanation: The process of electroplating takes place as metals in ionic form move from a positive to negative electrode. An electric current passing through the ... ability of metal objects. Plating protects by one of two ways, either sacrificially or mechanically.
Description : The metals with very low melting points which melts by the temperature of palm are A) Sodium and potassium B) Lead and magnesium C) Aluminium and zinc D) Gallium and caesium
Last Answer : D) Gallium and caesium
Description : The metals commonly used for electroplating are (1) Gold, Sodium and Chromium (2) Chromium, Copper and Nickel (3) Nickel, Lead and Chromium (4) Gold, Sodium and Potassium
Last Answer : Chromium, Copper and Nickel
Description : The ratio of thermal & electrical conductivity is same for all the metals at the same temperature; and at around room temperature, this ratio is proportional to(where, T = absolute temperature, °K) (A) T (B) 1/T (C) T2 (D) 1/T2
Last Answer : A) T
Description : Which of the following metals can be obtained from its ore only by electrolysis of a molten salt ? w) cobalt x) chromium y) copper z) sodium
Last Answer : ANSWER: Z -- SODIUM
Description : Which one of the following elements exists in liquid state at room temperature? (1) Mercury (2) Lead (3) Sodium (4) Calcium
Last Answer : (1) Mercury Explanation: Mercury is a dense, silvery dblock element. It is the only metal that is liquid at standard conditions for temperature and pressure.
Description : (3) reflection of light due to the presence of free electrons Explanation: Lustre (or luster) is the way light interacts with the surface of a crystal, rock, or mineral. The word ... conductivity, and high density. Typically they are malleable and ductile, deforming -under stress without cleaving.
Last Answer : Cloud is a colloidal dispersion of – (1) Air in a dispersion medium of water (2) Fog in a dispersion medium of water (3) Mist in a dispersion medium of air (4) Water drops in a dispersion medium of air
Description : On a cold day when the room temperature is 15°C, the metallic cap of a pen becomes much colder than its plastic body, though both are at the same temperature of 15°C, because - (1) metals ... metals (3) metals are good conductors of heat (4) plastics have a higher thermal conductivity than metals
Last Answer : (3) metals are good conductors of heat Explanation: On a chilly day, the room temperature is lower than our body temperature. Since metals have a higher coefficient of thermal conductivity than plastic, they ... from our fingers will flow to the metal cap much more quickly than to the plastic body.
Description : Which °fine metals has the maximum thermal conductivity? (1) Iron (2) Aluminium (3) Silver (4) Copper
Last Answer : (3) Silver Explanation: Silver has the best thermal conductivity of 429 W/mK at RT (295K). It is followed by copper, gold and aluminium. Metals generally have very good electrical conductivity, that leads to high thermal conductivity.
Description : Refractory metals are known for which of the following properties: w) lack of chemical reactivity x) low density y) high melting point z) high thermal conductivity
Last Answer : ANSWER: Y -- HIGH MELTING POINT
Description : A bimetallic strip commonly found in home furnace thermostats works because of the difference in this property of the two metals. Is it: w) thermal shock x) thermal conductivity y) thermal expansion z) thermal diffusivity
Last Answer : ANSWER: Y -- THERMAL EXPANSION
Description : On a cold day when the room temperature is 15°C, the metallic cap of a pen becomes much colder than its plastic body, though both are at the same temperature of 15°C, because : (1) metals ... metals (3) metals are good conductors of heat (4) plastics have a higher thermal conductivity than metals
Last Answer : metals are good conductors of heat
Description : Which of the metals has the maximum thermal conductivity? (1) Iron (2) Aluminium (3) Silver (4) Copper
Last Answer : Silver
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 : Liquid metal (e.g., molten sodium) is preferred as a coolant in case of a/an __________ reactor. (A) Homogeneous (B) Graphite moderated (C) Fast breeder (D) Enriched uranium (3% U-235) fuelled
Last Answer : (C) 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 : Tin base and lead base alloys are used for bearing materials. Tin compared to lead has lower (A) Price (B) Corrosion resistance (C) Thermal conductivity (D) Abundant availability
Last Answer : (D) Abundant availability
Description : Pick out the wrong statement. (A) Copper is the metal having the highest electronic conductivity (B) Hardenability & Weldability of metals are inversely related (C) Covalent bonding formed by ... all semiconductor materials (D) Glass transition temperature applies to 'polymers' but not to 'glasses'
Last Answer : Option A
Description : Which of the following metals reacts violently with water? (A) Mercury (B) Sodium (C) Calcium (D) Magnesium
Last Answer : Option B
Description : There are thirteen metals which are treated as pollutants. Which of the following metals is not a pollutant? (A) Mercury (B) Arsenic (C) Aluminium (D) Lead
Last Answer : (C) Aluminium
Description : Power consumption during turbulent flow in agitation tank is proportional to the __________ of the liquid. (A) Viscosity (B) Thermal conductivity (C) Surface tension (D) Density
Last Answer : (D) Density
Description : The type of liquor circulation system to be ' employed in evaporators (viz. natural or forced circulation) is determined mainly by the __________ of the liquid. (A) Viscosity (B) Density (C) Thermal conductivity (D) Corrosive nature
Last Answer : (A) Viscosity
Description : Pick out the wrong statement. (A) Bubble size increases with the dynamic viscosity of the liquid in case of nucleate pool boiling (B) Thermal conductivity of a dry material is more than ... in kg/hr in an evaporator (D) Vaporisation of organic substances in evaporator mostly causes foam formation
Last Answer : (B) Thermal conductivity of a dry material is more than that of the damp material
Description : Velocity of liquid hydrocarbon fuels in a pipeline cannot be measured by magnetic flow-meters, because their __________ is very low/small. (A) Thermal conductivity (B) Electrical conductivity (C) Specific gravity
Last Answer : (C) Specific gravity
Description : Which of the following has the highest thermal conductivity? (A) Brick (B) Air (C) Water (D) Silver
Last Answer : (D) Silver
Description : Sodium sulphur battery is a type of molten-salt battery constructed from _____ sodium and sulphur. • Solid • Liquid • Plasma • Gases
Last Answer : • Liquid
Description : Which of the following is incorrect? (a) Mercury: Hg (b) Silver: Ag (c) Sodium: Na (d) Potassium: Ka
Last Answer : Ans:(d)
Description : What Lead and mercury are two environmental pollutants why are they called heavy metals?
Last Answer : Need answer
Description : Which of the following metals contribute to to biomagnifications problem in the ecosystem? (1) Mercury (2) Chromium (3) (4) Copper (4) (4) Lead
Last Answer : (1) Mercury Explanation: Mercury causes biomagnification problem in the ecosystem.
Description : The toxicity of which of the following heavy metals leads to liver cirrbosis? (1) Copper (2) Lead (3) Mercury (4) Zinc
Last Answer : (1) Copper Explanation: Cirrhosis is a consequence of chronic liver disease characterized by replacement of liver tissue by fibrosis, scar tissue and regenerative nodules (lumps that occur as a result ... cause cirrhosis include Wilson's disease (which causes an accumulation of copper in the body).
Description : Which of the following metals form an amalgam with other metals? (1) Lead (2) Tin (3) Zinc (4) Mercury
Last Answer : (4) Mercury Explanation: An amalgam is a substance formed by the reaction of mercury with another metal. Almost all metals can form amalgams with mercury, notable exception being iron. Silver- ... "excellent and versatile restorative material" and is used in dentistry for a number of reasons.
Description : The toxicity of which of the following heavy metals leads to Liver cirrhosis? A. Copper (Answer) B. Lead C. Mercury D. Zinc
Last Answer : A. Copper (Answer)
Last Answer : Copper
Description : Which of the following metals form an amalgam with other metals ? (1) Lead (2) Tin (3) Zinc (4) Mercury
Last Answer : Mercury
Description : Which one of the following metals is used to galvanise iron ? (1) Copper (2) Lead (3) Zinc (4) Mercury
Last Answer : Zinc
Description : Which of the following metals contribute to to biomagnification problem in the ecosystem ? (1) Mercury (2) Chromium (4) Copper (4) Lead
Description : In Gas-Liquid Chromatography, some of the samples need to be derivatized in order to increase their (A) volatility (B) solubility (C)thermal conductivity (D) polarizability
Last Answer : (D) polarizability
Description : Which of the following building materials has the HIGHEST thermal conductivity? w) Southern pine wood x) common brick y) aluminum z) gypsum board or drywall
Last Answer : ANSWER: Y -- ALUMINUM
Description : Which one of the following metals does not react with water to produce Hydrogen? (1) Cadmium (2) Lithium (3) Potassium (4) Sodium
Last Answer : (1) Cadmium Explanation: A cadmium metal does not react with water to produce Hydrogen.
Description : Which one of the following metals does not react with water to produce Hydrogen ? (1) Potassium (2) Cadmium (3) Sodium (4) Lithium
Last Answer : (2) Cadmium Explanation: Cadmium is a soft, malleable, ductile, bluish-white divalent metal. It is similar in many respects to zinc but forms complex compounds. Unlike other metals, cadmium is ... occurs as a minor component in most zinc ores and therefore is a byproduct of zinc production.
Description : State as to why: (a) A solution of Na2CO3 is alkaline? (b)alkali metals are prepared by electrolysis of their fused chlorides ? (c)sodium is found to be more useful than potassium ?
Last Answer : Ans. (a) It undergoes hydrolysis to produce a strong base NaOH . (b) When the aq. Solution of any alkali metal is subjected to electrolysis ,H2 instead of the alkali metal is produced at the ... of sugars and amino acids into the cells. Thus, sodium is found to be more useful than potassium.
Last Answer : Cadmium
Description : The ratio of hydrodynamic boundary layer to thermal boundary layer thickness in case of liquid metals is (A) < 1 (B) 1 (C) > 1 (D) 2
Last Answer : (A) < 1
Description : The Dittus-Boelter equation for convective heat transfer [(i.e. h = 0.023 (K/D) (Re) 0.8 (Pr) 0.4 ] cannot be used for (A) Low Reynold's number (B) Very low Grashoff number (C) Molten metals (D) All (A), (B) and (C)
Last Answer : (D) All (A), (B) and (C)