Thickness of stock does not affect the fuel economy of furnaces, if thematerial to be heated is of(A) Low emissivity(B) High thermal conductivity(C) Both (A) and (B)(D) Neither (A) nor (B)

Thickness of stock does not affect the fuel economy of furnaces, if thematerial to be heated is of
(A) Low emissivity
(B) High thermal conductivity
(C) Both (A) and (B)
(D) Neither (A) nor (B)
by

1 Answer

Answer :

(C) Both (A) and (B)
by

Related questions

reduction in thermal resistance during heat transfer does not occur in the (A) Convection heat transfer by stirring the fluid and cleaning the heating surface (B) Conduction heat transfer by reduction in the material thickness and increase in the thermal conductivity (C) Radiation heat transfer by increasing the temperature and reducing the emissivity (D) None of these

Description : reduction in thermal resistance during heat transfer does not occur in the (A) Convection heat transfer by stirring the fluid and cleaning the heating surface (B) Conduction heat transfer by ... Radiation heat transfer by increasing the temperature and reducing the emissivity (D) None of these

Last Answer : Option C

In a furnace, the heat taken by the charge/stock and the heat lost to the furnace structure & flue gases depends on the (A) Rate of firing and emissivity of flame (B) Thermal conductivity of the charge & structural materials of furnace (C) Nature of process; whether batch, continuous or intermittent (D) All (A), (B) and (C)

Description : In a furnace, the heat taken by the charge/stock and the heat lost to the furnace structure & flue gases depends on the (A) Rate of firing and emissivity of flame (B) Thermal conductivity of the charge & ... (C) Nature of process; whether batch, continuous or intermittent (D) All (A), (B) and (C)

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

The heating capacity of muffle furnace depends on the (A) Surface area & emissivity of the stock (B) Properties of the muffle wall (temperature, area, and emissivity) (C) Both (A) & (B) (D) Neither (A) nor (B)

Description : The heating capacity of muffle furnace depends on the (A) Surface area & emissivity of the stock (B) Properties of the muffle wall (temperature, area, and emissivity) (C) Both (A) & (B) (D) Neither (A) nor (B)

Last Answer : (C) Both (A) & (B)

LSHS is a type of furnace oil, which (A) Is more viscous than high viscosity furnace oil (HVFO) (B) Stands for low sulphur heavy stock (C) Is an ideal fuel for metallurgical furnaces due to its lower sulphur content (< 1%(D) All (A), (B) and (C))

Description : LSHS is a type of furnace oil, which (A) Is more viscous than high viscosity furnace oil (HVFO) (B) Stands for low sulphur heavy stock (C) Is an ideal fuel for metallurgical furnaces due to its lower sulphur content (< 1%) (D) All (A), (B) and (C)

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

Which of the following variables affects the furnace capacity? (A) Temperature of flue gas (B) Thermal conductivity of stock (C) Thickness of heating stock(D) All (A), (B) and (C)

Description : Which of the following variables affects the furnace capacity? (A) Temperature of flue gas (B) Thermal conductivity of stock (C) Thickness of heating stock (D) All (A), (B) and (C)

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

Thermal conductivity of a conducting solid material depends upon its (A) Temperature (B) Porosity (C) Both (A) & (B) (D) Neither (A) nor (B)

Description : Thermal conductivity of a conducting solid material depends upon its (A) Temperature (B) Porosity (C) Both (A) & (B) (D) Neither (A) nor (B)

Last Answer : (C) Both (A) & (B)

Heat transfer rate to the stock/charge in the furnace does not depend upon the(A) Emissivity of the refractory walls(B) Size of the furnace(C) Use of waste heat recovery equipments(D) Thickness of the stock

Description : Heat transfer rate to the stock/charge in the furnace does not depend upon the (A) Emissivity of the refractory walls (B) Size of the furnace (C) Use of waste heat recovery equipments (D) Thickness of the stock

Last Answer : (C) Use of waste heat recovery equipments

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

Plutonium (A) Is recovered from spent fuel from thermal nuclear reactor (B) Has much lower melting point (640°C ) compared to thorium (1690°C) (C) Both (A) and (B) (D) Neither (A) nor (B)

Description : Plutonium (A) Is recovered from spent fuel from thermal nuclear reactor (B) Has much lower melting point (640°C ) compared to thorium (1690°C) (C) Both (A) and (B) (D) Neither (A) nor (B)

Last Answer : (C) Both (A) and (B

Fuel economy in furnaces can be achieved by (A) Using oxygen enriched combustion air (B) Preheating the combustion air (C) Reducing the heat loss through furnace openings & doors (D) All (A), (B) and (C

Description : Fuel economy in furnaces can be achieved by (A) Using oxygen enriched combustion air (B) Preheating the combustion air (C) Reducing the heat loss through furnace openings & doors (D) All (A), (B) and (C

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

A wall has two layers of materials A and B; each made of a different material. Both the layers have the same thickness. The thermal conductivity of material A is twice that of B. Under the equilibrium, the temperature difference across the wall is 36°C. The temperature difference across the layer A is __________ °C. (A) 6 (B) 12 (C) 18 (D) 24

Description : A wall has two layers of materials A and B; each made of a different material. Both the layers have the same thickness. The thermal conductivity of material A is twice that of B. Under the equilibrium, the temperature ... difference across the layer A is __________ °C. (A) 6 (B) 12 (C) 18 (D) 24

Last Answer : (B) 12

Thermocol (expanded polystyrene) is not used for (A) Low temperature thermal insulation as in refrigerator and air conditioners (B) Acoustic control and ceiling for building (C) High temperature thermal insulation in furnaces (D) Packing of delicate electronic gadgets

Description : Thermocol (expanded polystyrene) is not used for (A) Low temperature thermal insulation as in refrigerator and air conditioners (B) Acoustic control and ceiling for building (C) High temperature thermal insulation in furnaces (D) Packing of delicate electronic gadgets

Last Answer : (C) High temperature thermal insulation in furnaces

How would the economy be affected if everyone holding stock neither bought nor sold shares for, say, a week?

Description : How would the economy be affected if everyone holding stock neither bought nor sold shares for, say, a week?

Last Answer : it would stay flat and sidewise. people would be going long term- then when it broke- there’d be lots of money to make

The heat flux (from outside to inside) across an insulating wall with thermal conductivity, K = 0.04 W/m.°K and thickness 0.16m is 10 W/m2 . The temperature of the inside wall is - 5°C. The outside wall temperature is (A) 25°C (B) 30°C (C) 35°C (D) 40°C

Description : The heat flux (from outside to inside) across an insulating wall with thermal conductivity, K = 0.04 W/m.°K and thickness 0.16m is 10 W/m2 . The temperature of the inside wall is - 5°C. The outside wall temperature is (A) 25°C (B) 30°C (C) 35°C (D) 40°C

Last Answer : (C) 35°C

Pick out the wrong statement. (A) Reciprocal of the resistance to heat flow is called thermal conductance (B) Unit of thermal conductance is W/°K (C) Thermal conductance of a wall of thickness 'L', thermal conductivity 'k' and heat flow area 'A' is kL/A (D) None of these

Description : Pick out the wrong statement. (A) Reciprocal of the resistance to heat flow is called thermal conductance (B) Unit of thermal conductance is W/°K (C) Thermal conductance of a wall of thickness 'L', thermal conductivity 'k' and heat flow area 'A' is kL/A (D) None of these

Last Answer : (C) Thermal conductance of a wall of thickness 'L', thermal conductivity 'k' and heat flow area 'A' is kL/A

A composite flat wall of a furnace is made of two materials 'A' and 'B'. The thermal conductivity of 'A' is twice of that of material 'B', while the thickness of layer of 'A' is half that of B. If the temperature at the two sides of the wall are 400 and 1200°K, then the temperature drop (in °K) across the layer of material 'A' is (A) 125 (B) 133 (C) 150 (D) 160

Description : A composite flat wall of a furnace is made of two materials 'A' and 'B'. The thermal conductivity of 'A' is twice of that of material 'B', while the thickness of layer of 'A' is half that of B. If the temperature ... drop (in °K) across the layer of material 'A' is (A) 125 (B) 133 (C) 150 (D) 160

Last Answer : (D) 160

The left face of a one dimensional slab of thickness 0.2 m is maintained at 80°C and the right face is exposed to air at 30°C. The thermal conductivity of the slab is 1.2 W/m.K and the heat transfer co-efficient from the right face is 10 W/m2 .K. At steady state, the temperature of the right face in °C is (A) 77.2 (B) 71.2 (C) 63.8 (D) 48.7

Description : The left face of a one dimensional slab of thickness 0.2 m is maintained at 80°C and the right face is exposed to air at 30°C. The thermal conductivity of the slab is 1.2 W/m.K and the heat transfer co-efficient from the ... temperature of the right face in °C is (A) 77.2 (B) 71.2 (C) 63.8 (D) 48.7

Last Answer : (D) 48.7

Heat transfer rate described by Fourier's law will decrease, if the __________ increases. (A) Thermal conductivity (B) Thickness (C) Temperature difference (D) Heat transfer area

Description : Heat transfer rate described by Fourier's law will decrease, if the __________ increases. (A) Thermal conductivity (B) Thickness (C) Temperature difference (D) Heat transfer area

Last Answer : (B) Thickness

Conductance is given by (where, x = thickness, A = heat flow area, K = thermal conductivity.) (A) x/KA (B) KA/x (C) K/Ax (D) A/Kx

Description : Conductance is given by (where, x = thickness, A = heat flow area, K = thermal conductivity.) (A) x/KA (B) KA/x (C) K/Ax (D) A/Kx

Last Answer : (B) KA/x

Three materials A, B and C of equal thickness and of thermal conductivity of 20, 40 & 60 kcal/hr. m. °C respectively are joined together. The temperature outside of A and C are 30°C and 100°C respectively. The interface between B and C will be at a temperature of __________ °C. (A) 40 (B) 95 (C) 70 (D) 50

Description : Three materials A, B and C of equal thickness and of thermal conductivity of 20, 40 & 60 kcal/hr. m. °C respectively are joined together. The temperature outside of A and C are 30°C and 100°C respectively. The interface ... C will be at a temperature of __________ °C. (A) 40 (B) 95 (C) 70 (D) 50

Last Answer : (C) 70

Walls of a cubical oven are of thickness l, and they are made of material of thermal conductivity k. The temperature inside the oven is 100°C and the inside heat transfer co-efficient is ‘3k/l’. If the wall temperature on the outside is held at 25°C, what is the inside wall temperature in degree centigrade?(A) 35.5 (B) 43.75 (C) 81.25 (D) 48.25

Description : Walls of a cubical oven are of thickness l, and they are made of material of thermal conductivity k. The temperature inside the oven is 100°C and the inside heat transfer co-efficient is 3k/l'. If the wall temperature ... wall temperature in degree centigrade? (A) 35.5 (B) 43.75 (C) 81.25 (D) 48.25

Last Answer : (C) 81.25

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 thermal conductivity 0.14 W/m.K and thickness __________ metre. (A) 0.01 (B) 0.1 (C) 0.25 (D) 0.5

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

One face of a furnace wall is at 1030°C and the other face is exposed to room temperature (30°C). If the thermal conductivity of furnace wall is 3 W. m-1. k-1 and the wall thickness is 0.3 m, the maximum heat loss (in W/m) is (A) 100 (B) 900 (C) 9000 (D) 10000

Description : One face of a furnace wall is at 1030°C and the other face is exposed to room temperature (30°C). If the thermal conductivity of furnace wall is 3 W. m-1. k-1 and the wall thickness is 0.3 m, the maximum heat loss (in W/m) is (A) 100 (B) 900 (C) 9000 (D) 10000

Last Answer : (D) 10000

Filtration capacity of a rotary drum vacuum filter depends upon the (A) Cake thickness (B) Characteristics of the feed slurry (C) Both (A) & (B) (D) Neither (A) nor (B)

Description : Filtration capacity of a rotary drum vacuum filter depends upon the (A) Cake thickness (B) Characteristics of the feed slurry (C) Both (A) & (B) (D) Neither (A) nor (B)

Last Answer : (C) Both (A) & (B)

For __________ drying, the effects of velocity, temperature and humidity of the gas and the thickness of the solid are the same. (A) Unsaturated surface (B) Constant rate (C) Both (A) and (B) (D) Neither (A) nor (B)

Description : For __________ drying, the effects of velocity, temperature and humidity of the gas and the thickness of the solid are the same. (A) Unsaturated surface (B) Constant rate (C) Both (A) and (B) (D) Neither (A) nor (B)

Last Answer : (C) Both (A) and (B)

Soft coke is not (A) Produced by low temperature carbonisation of coal (B) A domestic fuel (C) Used in blast furnaces (D) None of these

Description : Soft coke is not (A) Produced by low temperature carbonisation of coal (B) A domestic fuel (C) Used in blast furnaces (D) None of these

Last Answer : (C) Used in blast furnaces

Example of an indirectly heated furnace is (A) Hood annealing furnace (B) Muffle furnace (C) Both (A) and (B)(D) Neither (A) nor (B)

Description : Example of an indirectly heated furnace is (A) Hood annealing furnace (B) Muffle furnace (C) Both (A) and (B) (D) Neither (A) nor (B)

Last Answer : (C) Both (A) and (B)

What happens to thermal conductivity of a wall if its thickness double?

Description : What happens to thermal conductivity of a wall if its thickness double?

Last Answer : Need answer

How is the rate of a cooling of a building affected by the thickness and the thermal conductivity of its walls?

Description : How is the rate of a cooling of a building affected by the thickness and the thermal conductivity of its walls?

Last Answer : Generally thicker walls slow down the transfer of heat, and if the material is a good thermal conductor that will increase the rate of transfer.

Which of the following is the formula for thermal resistance?  A. Thickness of material/ thermal conductivity of material  B. 2(thickness of material)/thermal conductivity of material  C. Thickness of material/ 2(thermal conductivity of material)  D. Thickness of material x thermal conductivity of material

Description : Which of the following is the formula for thermal resistance?  A. Thickness of material/ thermal conductivity of material  B. 2(thickness of material)/thermal conductivity of material  C. ... / 2(thermal conductivity of material)  D. Thickness of material x thermal conductivity of material

Last Answer : Thickness of material/ thermal conductivity of material

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 that of the damp material (C) Ratio of its capacity to economy equals the steam consumption in kg/hr in an evaporator (D) Vaporisation of organic substances in evaporator mostly causes foam formation

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

ideal material for making cooking vessels should have (A) High heat capacity (B) Low heat capacity (C) High thermal conductivity (D) Both (B) and (C)

Description : ideal material for making cooking vessels should have (A) High heat capacity (B) Low heat capacity (C) High thermal conductivity (D) Both (B) and (C)

Last Answer : Option D

Nominal Pipe Size (NPS) of a pipe less than 12 inches in diameter indicates its(A) Inner diameter(B) Outer diameter(C) Thickness(D) Neither inner nor outer diameter

Description : Nominal Pipe Size (NPS) of a pipe less than 12 inches in diameter indicates its (A) Inner diameter (B) Outer diameter (C) Thickness (D) Neither inner nor outer diameter

Last Answer : (D) Neither inner nor outer diameter

Which of the following statements comparing transistors and vacuum tubes is correct? A. Both transistors and vacuum tubes have a cathode that must be heated to give off electrons. B. A vacuum tube must have a heated cathode, where transistors do not. C. Neither transistors nor vacuum tubes require heat for electrons to flow. D. The anode of both transistors and vacuum tubes must be heated to give off electrons.

Description : Which of the following statements comparing transistors and vacuum tubes is correct? A. Both transistors and vacuum tubes have a cathode that must be heated to give off electrons. B. A vacuum tube must ... flow. D. The anode of both transistors and vacuum tubes must be heated to give off electrons.

Last Answer : Answer: B

Tar is a better fuel than furnace oil, because of its (A) Higher calorific value (B) Lower sulphur content (C) Higher emissivity (0.8-0.9) resulting in higher radiation heat transfer rate (D) Both (A) and (B)

Description : Tar is a better fuel than furnace oil, because of its (A) Higher calorific value (B) Lower sulphur content (C) Higher emissivity (0.8-0.9) resulting in higher radiation heat transfer rate (D) Both (A) and (B)

Last Answer : (D) Both (A) and (B)

A bolometer is (A) Used for the measurement of thermal radiation (B) An element which senses optical input and delivers thermal output (C) Both (A) & (B) (D) Neither (A) nor (B)

Description : A bolometer is (A) Used for the measurement of thermal radiation (B) An element which senses optical input and delivers thermal output (C) Both (A) & (B) (D) Neither (A) nor (B)

Last Answer : (C) Both (A) & (B)

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

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

The heating capacity of continuous reheating furnace depends upon the (A) Hearth area and furnace temperature (B) Emissivity of the stock (C) Ratio of wall surface to stock surface (D) All (A), (B) and (C)

Description : The heating capacity of continuous reheating furnace depends upon the (A) Hearth area and furnace temperature (B) Emissivity of the stock (C) Ratio of wall surface to stock surface (D) All (A), (B) and (C)

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

Economy of a multiple effect evaporator depends upon the (A) Heat balance consideration (B) Rate of heat transfer (C) Both (A) and (B) (D) Neither (A) nor (B

Description : Economy of a multiple effect evaporator depends upon the (A) Heat balance consideration (B) Rate of heat transfer (C) Both (A) and (B) (D) Neither (A) nor (B

Last Answer : (A) Heat balance consideration

Means for giving direction to the circulation of gases in furnaces are (A) Fans (B) Arrangement of heating stock in the furnaces (C) Location of outlet ports and heating & combustion devices (D) All (A), (B) and (C)

Description : Means for giving direction to the circulation of gases in furnaces are (A) Fans (B) Arrangement of heating stock in the furnaces (C) Location of outlet ports and heating & combustion devices (D) All (A), (B) and (C)

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

In which of the following furnaces, the gases are sucked through the stock bed from below? (A) Soaking pit (B) Sintering machine (C) Beehive oven (D) None of these

Description : In which of the following furnaces, the gases are sucked through the stock bed from below? (A) Soaking pit (B) Sintering machine (C) Beehive oven (D) None of these

Last Answer : (B) Sintering machine

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

A __________ surface has the maximum thermal emissivity out of the following. (A) Black & smooth (B) Black & rough (C) White & smooth (D) White & rough

Description : A __________ surface has the maximum thermal emissivity out of the following. (A) Black & smooth (B) Black & rough (C) White & smooth (D) White & rough

Last Answer : (B) Black & rough

The thermal radiative flux from a surface of emissivity = 0.4 is 22.68 kW/m2 . The approximate surface temperature (K) is (Stefan-Boltzmann constant = 5.67 × 10 -8 W/m2 .K4 )(A) 1000(B) 727(C) 800(D) 1200

Description : The thermal radiative flux from a surface of emissivity = 0.4 is 22.68 kW/m2 . The approximate surface temperature (K) is (Stefan-Boltzmann constant = 5.67 × 10 -8 W/m2 .K4 ) (A) 1000 (B) 727 (C) 800 (D) 1200

Last Answer : (A) 1000

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

Which of the following furnaces will have maximum thermal efficiency? (A) Soaking pits (B) Walking beam reheating furnace (C) Boiler furnace (D) Rotary kilns

Description : Which of the following furnaces will have maximum thermal efficiency? (A) Soaking pits (B) Walking beam reheating furnace (C) Boiler furnace (D) Rotary kilns

Last Answer : (C) Boiler furnace

Thermal efficiency of furnaces can be improved by (A) Waste heat recovery from flue gas (B) Minimising heat losses from furnace walls(C) Maintaining proper draught(D) All (A), (B) and (C

Description : Thermal efficiency of furnaces can be improved by (A) Waste heat recovery from flue gas (B) Minimising heat losses from furnace walls (C) Maintaining proper draught (D) All (A), (B) and (C

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

The heat recoverable from flue gases of furnaces depends on the (A) Thermal efficiency of furnace (B) Quantity of flue gases (C) Flue gas temperature drop through the furnace (D) All (A), (B) and (C)

Description : The heat recoverable from flue gases of furnaces depends on the (A) Thermal efficiency of furnace (B) Quantity of flue gases (C) Flue gas temperature drop through the furnace (D) All (A), (B) and (C)

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

A fast breeder reactor (A) Uses natural uranium as fuel (B) Does not require a moderator (C) Both (A) and (B) (D) Neither (A) nor (B)

Description : A fast breeder reactor (A) Uses natural uranium as fuel (B) Does not require a moderator (C) Both (A) and (B) (D) Neither (A) nor (B)

Last Answer : (B) Does not require a moderator

In a furnace operation, which is not preheated? (A) Solid fuels (B) Hydrocarbon containing fuel gases (e.g. coke oven gas, refinery gas etc.) (C) Both (A) and (B) (D) Neither (A) nor (B)

Description : In a furnace operation, which is not preheated? (A) Solid fuels (B) Hydrocarbon containing fuel gases (e.g. coke oven gas, refinery gas etc.) (C) Both (A) and (B) (D) Neither (A) nor (B)

Last Answer : (C) Both (A) and (B)