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

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

by

1 Answer

Answer :

(D) Coke breeze

by

Related questions

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

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

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

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

Pick out the wrong statement: (A) With change in temperature, the radiant energy emitted by a black body remains unchanged (B) Absorptivity of a body approaches unity in case of diffuse reflection (C) Absorptivity of a perfectly black body is unity (D) Value of Stefan-Boltzmann constant is 4.876 × 10 -8 KCal/m2 .hr.°K4

Description : Pick out the wrong statement: (A) With change in temperature, the radiant energy emitted by a black body remains unchanged (B) Absorptivity of a body approaches unity in case of diffuse reflection (C) Absorptivity of ... unity (D) Value of Stefan-Boltzmann constant is 4.876 10 -8 KCal/m2 .hr.°K4

Last Answer : (A) With change in temperature, the radiant energy emitted by a black body remains unchanged

Absorptivity and reflectivity of a perfect black body are respectively (A) 1 and 0 (B) 0 and 1 (C) 1 and ∞ (D) 0 and 0.5

Description : Absorptivity and reflectivity of a perfect black body are respectively (A) 1 and 0 (B) 0 and 1 (C) 1 and ∞ (D) 0 and 0.5

Last Answer : (A) 1 and 0

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

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

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

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

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

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

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

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

Last Answer : (B) Tunnel

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

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

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

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

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

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

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

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

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

Description : 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

Last Answer : (A) Greater resistance to corrosion by slags

While the total emissivity of a perfect black body is unity, the same for a real body is(A) 0(B) 1(C) > 1(D) Between 0 and 1

Description : While the total emissivity of a perfect black body is unity, the same for a real body is (A) 0 (B) 1 (C) > 1 (D) Between 0 and 1

Last Answer : (D) Between 0 and 1

Height of coke oven is limited (say maximum upto 7 metres) mainly by the(A) Problem of uniform heating along its height(B) Structural strength of silica bricks(C) Problem in door cleaning(D) Buckling of ram of pusher car at the time of coke pushing

Description : Height of coke oven is limited (say maximum upto 7 metres) mainly by the (A) Problem of uniform heating along its height (B) Structural strength of silica bricks (C) Problem in door cleaning (D) Buckling of ram of pusher car at the time of coke pushing

Last Answer : (A) Problem of uniform heating along its height

Which of the following must be stored in silos and not in open yard? (A) Coke breeze (B) High V.M. bituminous coal (C) Sand (D) None of these

Description : Which of the following must be stored in silos and not in open yard? (A) Coke breeze (B) High V.M. bituminous coal (C) Sand (D) None of these

Last Answer : (B) High V.M. bituminous coal

Which of the following is not a manufactured fuel? (A) Coke breeze (B) Soft coke (C) Colloidal fuels (D) Charcoal

Description : Which of the following is not a manufactured fuel? (A) Coke breeze (B) Soft coke (C) Colloidal fuels (D) Charcoal

Last Answer : (A) Coke breeze

Which of the following would require least amount of secondary air for combustion? (A) Coke breeze containing 25% ash and 2% volatile matter (B) Anthracite containing 10% volatile matter and 8% ash(C) Bituminous coal containing 20% ash and 25% volatile matter(D) Semi-bituminous coal containing 25% ash and 20% volatile matter

Description : Which of the following would require least amount of secondary air for combustion? (A) Coke breeze containing 25% ash and 2% volatile matter (B) Anthracite containing 10% volatile matter and 8% ash ... ash and 25% volatile matter (D) Semi-bituminous coal containing 25% ash and 20% volatile matter

Last Answer : (A) Coke breeze containing 25% ash and 2% volatile matter

__________ is used as a flux in the smelting of copper ore like chalcopyrite. (A) Coke breeze (B) Lime powder (C) Silica/quartz (D) Dolomite

Description : __________ is used as a flux in the smelting of copper ore like chalcopyrite. (A) Coke breeze (B) Lime powder (C) Silica/quartz (D) Dolomite

Last Answer : (C) Silica/quartz

SO3 is absorbed using H2SO4 in a (A) Cast iron packed tower (B) Stainless steel plate tower (C) Packed steel tower lined with acid proof bricks (D) None of these

Description : SO3 is absorbed using H2SO4 in a (A) Cast iron packed tower (B) Stainless steel plate tower (C) Packed steel tower lined with acid proof bricks (D) None of these

Last Answer : (C) Packed steel tower lined with acid proof bricks

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

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

Last Answer : Answer: Option D

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

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

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

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

Last Answer : Answer: Option A

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

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

In thermal radiation for a black body (where, ε is emissivity and α is absorptivity) (A) α = 1; ε ≠ 1 (B) α ≠ 1, ε = 1 (C) α ≠ 1, ε ≠ 1 (D) α = 1; ε = 1

Description : In thermal radiation for a black body (where, ε is emissivity and α is absorptivity) (A) α = 1; ε ≠ 1 (B) α ≠ 1, ε = 1 (C) α ≠ 1, ε ≠ 1 (D) α = 1; ε = 1

Last Answer : (D) α = 1; ε = 1

What is the absorptivity of a black body? (A) 1 (B) 0 (C) 0.78 (D) 0.95

Description : What is the absorptivity of a black body? (A) 1 (B) 0 (C) 0.78 (D) 0.95

Last Answer : (A) 1

For an ideal black body (A) Absorptivity = 1 (B) Reflectivity = 1 (C) Emissivity = 0 (D) Transmissivity = 1

Description : For an ideal black body (A) Absorptivity = 1 (B) Reflectivity = 1 (C) Emissivity = 0 (D) Transmissivity = 1

Last Answer : (A) Absorptivity = 1

For the manufacture of concrete a low density, the aggregate used is (a) Furnace clinker (b) Coke breeze (c)Saw dust (d) All the above

Description : For the manufacture of concrete a low density, the aggregate used is (a) Furnace clinker (b) Coke breeze (c)Saw dust (d) All the above

Last Answer : (d) All the above

What is the absorptivity of a black body?  A. 0  B. 1  C. 0.5  D. 0.25

Description : What is the absorptivity of a black body?  A. 0  B. 1  C. 0.5  D. 0.25

Last Answer : 1

Perspex is nothing but (A) Acrylic sheet (B) An elastomer (C) An alloy of lead and tin (D) Aluminium foil clad with Bakelite

Description : Perspex is nothing but (A) Acrylic sheet (B) An elastomer (C) An alloy of lead and tin (D) Aluminium foil clad with Bakelite

Last Answer : (A) Acrylic sheet

Coke oven regenerators are made of __________ bricks. (A) Fire clay (B) Silica (C) Low thermal conductivity (D) High electrical conductivity

Description : Coke oven regenerators are made of __________ bricks. (A) Fire clay (B) Silica (C) Low thermal conductivity (D) High electrical conductivity

Last Answer : (A) Fire clay

Coke oven walls are lined with __________ bricks. (A) Silica (B) Tar-dolomite (C) Low thermal conductivity (D) Fire clay

Description : Coke oven walls are lined with __________ bricks. (A) Silica (B) Tar-dolomite (C) Low thermal conductivity (D) Fire clay

Last Answer : (A) Silica

Beehive coke ovens are made of __________ bricks.(A) Silica (B) Fireclay (C) Silicon carbide (D) Corundum

Description : Beehive coke ovens are made of __________ bricks. (A) Silica (B) Fireclay (C) Silicon carbide (D) Corundum

Last Answer : (A) Silica

In regenerative air preheater (as practised in heating of coke ovens), the heat is transferred (A) Through a metallic wall (B) By direct contact of hot flue gas with air (C) By heating an intermediate material (like chequor bricks) and then heating the air from this hot material (D) None of these

Description : In regenerative air preheater (as practised in heating of coke ovens), the heat is transferred (A) Through a metallic wall (B) By direct contact of hot flue gas with air (C) By ... material (like chequor bricks) and then heating the air from this hot material (D) None of these

Last Answer : (C) By heating an intermediate material (like chequor bricks) and then heating the air from this hot material

The loss tangent of a perfect dielectric will be a) Zero b) Unity c) Maximum d) Minimum

Description : The loss tangent of a perfect dielectric will be a) Zero b) Unity c) Maximum d) Minimum

Last Answer : d) Minimum

Why is extraction of aluminium not commercially viable by using reducing agents like coke? OR Coke is used in the extraction of iron but not in the extraction of aluminium. Why? OR Aluminium cannot be extracted by heating bauxite and coke. Why?

Description : Why is extraction of aluminium not commercially viable by using reducing agents like coke? OR Coke is used in the extraction of iron but not in the extraction of aluminium. Why? OR Aluminium cannot be extracted by heating bauxite and coke. Why?

Last Answer : Oxygen of aluminium oxide cannot be easily taken away by reducing agents like coke.

Can aluminium foil really block electrical signals from entering your brain?

Description : Can aluminium foil really block electrical signals from entering your brain?

Last Answer : I don’t think that works.

Why cast aluminium tri-foil clamp is used in single core cables laying?

Description : Why cast aluminium tri-foil clamp is used in single core cables laying?

Last Answer : When three conductors are clamped together the fluxes around the conductors are get cancelled  

State the functions of following essential parts of electrolytic capacitor. 1. Aluminium foil 2. Oxide film 3. Spacers 4. Aluminium container

Description : State the functions of following essential parts of electrolytic capacitor. 1. Aluminium foil 2. Oxide film 3. Spacers 4. Aluminium container

Last Answer : 1. Aluminium Foil – It serves as a positive electrode called anode  2. Oxide film – It acts as a dielectric medium.  3. Spacer- It is used to provide separation and hold the electrolyte.  4. Aluminium container- It serves as a negative electrode called cathode.

Which is the artificial form of aluminium oxide used for making refractory crucibles?

Description : Which is the artificial form of aluminium oxide used for making refractory crucibles?

Last Answer : Alundum

The sum of reflectivity and absorptivity for an opaque body is equal to (A) 0.5 (B) 1 (C) 0 (D) 2

Description : The sum of reflectivity and absorptivity for an opaque body is equal to (A) 0.5 (B) 1 (C) 0 (D) 2

Last Answer : (B) 1

The ratio of total radiating power to the absorptivity of the body depends upon the __________ as per Kirchoff’s law. (A) Wavelength of radiation (B) Nature of the body (C) Temperature of the body (D) None of these

Description : The ratio of total radiating power to the absorptivity of the body depends upon the __________ as per Kirchoff’s law. (A) Wavelength of radiation (B) Nature of the body (C) Temperature of the body (D) None of these

Last Answer : (C) Temperature of the body

The absorptivity of a body is equal to its emissivity (A) At a particular temperature (B) For circular bodies (C) Under thermal equilibrium (D) None of these

Description : The absorptivity of a body is equal to its emissivity (A) At a particular temperature (B) For circular bodies (C) Under thermal equilibrium (D) None of these

Last Answer : (C) Under thermal equilibrium

The absorptivity of a grey body at a given temperature __________ with increasing wavelength of radiation. (A) Increases (B) Decreases (C) Remain constant (D) May increase or decrease; depends on the material

Description : The absorptivity of a grey body at a given temperature __________ with increasing wavelength of radiation. (A) Increases (B) Decreases (C) Remain constant (D) May increase or decrease; depends on the material

Last Answer : (D) May increase or decrease; depends on the material

The silica is used for preparing (A) Silica bricks (B) Coke oven (C) Lining for glass furnaces (D) All of these

Description : The silica is used for preparing (A) Silica bricks (B) Coke oven (C) Lining for glass furnaces (D) All of these

Last Answer : Answer: Option D

plate used for cutting a inverting the soil. i. Cooper. c) iron ii. Aluminium. d) steel

Description : plate used for cutting a inverting the soil. i. Cooper. c) iron ii. Aluminium. d) steel

Last Answer : steel

Select insulating materials for following parts : (i) Insulation between heating element and base plate of electric iron. (ii) Insulation used over copper or aluminium conductor used for making coils. (iii) Transformer bushings. (iv) Insulation between transmission line and pole.

Description : Select insulating materials for following parts : (i) Insulation between heating element and base plate of electric iron. (ii) Insulation used over copper or aluminium conductor used for making coils. (iii) Transformer bushings. (iv) Insulation between transmission line and pole.

Last Answer : Parts Insulating Materials  Insulation between heating element and base plate of electric iron. Mica Insulation used over copper or aluminium conductor used for making coils.  ... Transformer bushings Porcelain  Insulation between transmission line and pole. Porcelain

What refers to the rate of thermal radiation emitter per unit area of a body?  A. Thermal conductivity  B. Absorptivity  C. Emissivity  D. Emissive power

Description : What refers to the rate of thermal radiation emitter per unit area of a body?  A. Thermal conductivity  B. Absorptivity  C. Emissivity  D. Emissive power

Last Answer : Emissive power

Pick out the wrong statement. (A) In the McCabe-Thiele diagram for binary distillation, vertical feed line represents saturated liquid feed and horizontal feed line represents saturated vapour feed (B) In small columns, local efficiency is larger than Murphree efficiency; in large columns local efficiency is smaller than Murphree efficiency (C) For Laminar flow over a plate of length L, the local mass transfer co￾efficient at a distance L from the leading edge is 1.5 × 10 -2m/s. Then the average mass transfer co-efficient for the plate is 2 × 10 -2m/s (D) The concentration and hydrodynamic boundary layers over a flat plate are of equal thickness, if Schmidt number is equal to unity

Description : Pick out the wrong statement. (A) In the McCabe-Thiele diagram for binary distillation, vertical feed line represents saturated liquid feed and horizontal feed line represents saturated vapour feed (B) In ... layers over a flat plate are of equal thickness, if Schmidt number is equal to unity

Last Answer : (C) For Laminar flow over a plate of length L, the local mass transfer co￾efficient at a distance L from the leading edge is 1.5 × 10 -2m/s. Then the average mass transfer co-efficient for the plate is 2 × 10 -2m/s

Pick out the correct statement. (A) The slope of the stripping line is always less than unity (B) For a given separation in a binary distillation column, with increase in reflux ratio (above the minimum reflux ratio), the fixed cost of the distillation column first increases and then decreases (C) In Ponchon-Savarit method of no. of theoretical plate determination, the stripping and rectifying operating lines are vertical at total reflux (D) Kremser-Brown-Souder's equation is used to calculate the efficiency of a plate tower

Description : Pick out the correct statement. (A) The slope of the stripping line is always less than unity (B) For a given separation in a binary distillation column, with increase in reflux ratio ( ... (D) Kremser-Brown-Souder's equation is used to calculate the efficiency of a plate tower

Last Answer : C) In Ponchon-Savarit method of no. of theoretical plate determination, the stripping and rectifying operating lines are vertical at total reflux