Loss of heat from untagged steam pipe to the ambient air is by (A) Conduction (B) Convection (C) Radiation (D) All (A), (B) & (C)

Loss of heat from untagged steam pipe to the ambient air is by
(A) Conduction
(B) Convection
(C) Radiation
(D) All (A), (B) & (C)
by

1 Answer

Answer :

(D) All (A), (B) & (C)
by

Related questions

Fourier's law applies to the heat transfer by (A) Convection (B) Radiation (C) Conduction (D) All (A), (B) & (C)

Description : Fourier's law applies to the heat transfer by (A) Convection (B) Radiation (C) Conduction (D) All (A), (B) & (C)

Last Answer : (C) Conduction

When warm and cold liquids are mixed, the heat transfer is mainly by (A) Conduction (B) Convection (C) Radiation (D) Both (A) & (C

Description : When warm and cold liquids are mixed, the heat transfer is mainly by (A) Conduction (B) Convection (C) Radiation (D) Both (A) & (C

Last Answer : (B) Convection

Heat transfer by __________ is almost absent in case of fluidised bed drying operation. (A) Radiation (B) Conduction (C) Convection (D) Both (B) & (C)

Description : Heat transfer by __________ is almost absent in case of fluidised bed drying operation. (A) Radiation (B) Conduction (C) Convection (D) Both (B) & (C)

Last Answer : A) Radiation

Heat transfer to the water wall in a high pressure water wall type boiler furnace is mainly by (A) Conduction (B) Convection (C) Radiation (D) Both 'a' & 'b'

Description : Heat transfer to the water wall in a high pressure water wall type boiler furnace is mainly by (A) Conduction (B) Convection (C) Radiation (D) Both 'a' & 'b'

Last Answer : Option C

Even after sunset, the air near the Earth's surface continue to receive heat due to – (1) Insolation (2) Terrestrial Radiation (3) Conduction (4) Convection

Description : Even after sunset, the air near the Earth's surface continue to receive heat due to – (1) Insolation (2) Terrestrial Radiation (3) Conduction (4) Convection

Last Answer : (2) Terrestrial Radiation Explanation: Even after the sunset when the sun goes down, the incoming radiation from the sun stops, but there is still a lot of radiation that has been absorbed ... i.e. terrestrial radiation heats up the atmosphere more than the incoming solar radiation i.e. insolation

The mcrease in heat dissipation by air blasts is due to increase in (a) conduction (b) convection (e) radiation (d) any ofthe above

Description : The mcrease in heat dissipation by air blasts is due to increase in (a) conduction (b) convection (e) radiation (d) any ofthe above

Last Answer : (b) convection

Even after sunset, the air near the Earth’s surface continue to receive heat due to (1) Insolation (2) Terrestrial Radiation (3) Conduction (4) Convection

Description : Even after sunset, the air near the Earth’s surface continue to receive heat due to (1) Insolation (2) Terrestrial Radiation (3) Conduction (4) Convection

Last Answer : Terrestrial Radiation

Heat transfer in the laminar sub-layer in case of a liquid flowing through a pipe, is mostly by (A) Eddies current (B) Conduction (C) Convection (D) None of these

Description : Heat transfer in the laminar sub-layer in case of a liquid flowing through a pipe, is mostly by (A) Eddies current (B) Conduction (C) Convection (D) None of these

Last Answer : (B) Conduction

In pipe flow, heat is transferred from hot wall to the liquid by(A) Conduction only (B) Forced convection only (C) Forced convection and conduction (D) Free and forced convection

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Last Answer : (C) Forced convection and conduction

Which of the following statements regarding evacuated tube collectors (ETC) are true? i) ETC is used for high temperatures upto 150oC ii) because of use of vacuum between two concentric glass tube, higher amount of heat is retained in ETC iii) heat loss due to conduction back to atmosphere from ETC is high iv) performance of evacuated tube is highly dependent upon the ambient temperature i & iii b) ii & iii c) i & iv d) i & ii

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Last Answer : d) i & ii

In which mode of heat transfer, the Biot number is important? (A) Transient heat conduction (B) Natural convection (C) Forced convection (D) Radiation

Description : In which mode of heat transfer, the Biot number is important? (A) Transient heat conduction (B) Natural convection (C) Forced convection (D) Radiation

Last Answer : (A) Transient heat conduction

Mode of heat transfer in which the fluid moves under the influence of changes in fluid pressure produced by external work is called (A) Radiation (B) Natural convection (C) Forced convection (D) Conduction

Description : Mode of heat transfer in which the fluid moves under the influence of changes in fluid pressure produced by external work is called (A) Radiation (B) Natural convection (C) Forced convection (D) Conduction

Last Answer : (C) Forced convection

If heat transfer rate varies with the time, it is termed as (A) Forced convection (B) Steady state conduction (C) Monochromatic radiation (D) None of these

Description : If heat transfer rate varies with the time, it is termed as (A) Forced convection (B) Steady state conduction (C) Monochromatic radiation (D) None of these

Last Answer : (D) None of these

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

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

View factor is important in heat transfer by (A) Steady state conduction (B) Natural convection (C) Forced convection (D) Radiation

Description : View factor is important in heat transfer by (A) Steady state conduction (B) Natural convection (C) Forced convection (D) Radiation

Last Answer : (D) Radiation

Heat transfer by __________ may not necessarily require the presence of a medium. (A) Conduction (B) Natural convection (C) Forced convection (D) Radiation

Description : Heat transfer by __________ may not necessarily require the presence of a medium. (A) Conduction (B) Natural convection (C) Forced convection (D) Radiation

Last Answer : (D) Radiation

In furnaces operating at very high temperature (say) 1250°C, e.g. soaking pit), the maximum heat transfer takes place by (A) Conduction (B) Convection (C) Radiation (D) Cannot be predicted

Description : In furnaces operating at very high temperature (say) 1250°C, e.g. soaking pit), the maximum heat transfer takes place by (A) Conduction (B) Convection (C) Radiation (D) Cannot be predicted

Last Answer : (C) Radiation

In reverberatory furnace, charge is heated mainly by (A) Conduction (B) Natural convection (C) Radiation of heat from the roof of the combustion chamber (D) None of these

Description : In reverberatory furnace, charge is heated mainly by (A) Conduction (B) Natural convection (C) Radiation of heat from the roof of the combustion chamber (D) None of these

Last Answer : (C) Radiation of heat from the roof of the combustion chamber

Maximum heat transfer in high temperature furnaces is by (A) Conduction (B) Convection (C) Radiation (D) Either (A), (B) or (C); depends on the type of furnace

Description : Maximum heat transfer in high temperature furnaces is by (A) Conduction (B) Convection (C) Radiation (D) Either (A), (B) or (C); depends on the type of furnace

Last Answer : (C) Radiation

In salt bath furnace, heat is transferred to the charge mainly by (A) Conduction (B) Convection (C) Radiation (D) None of these

Description : In salt bath furnace, heat is transferred to the charge mainly by (A) Conduction (B) Convection (C) Radiation (D) None of these

Last Answer : (A) Conduction

Gibbs phase rule finds application, when heat transfer occurs by (A) Conduction (B) Convection (C) Radiation (D) Condensation

Description : Gibbs phase rule finds application, when heat transfer occurs by (A) Conduction (B) Convection (C) Radiation (D) Condensation

Last Answer : (D) Condensation

In a furnace with heating element temperature at 1700°C, the dominant mechanism of heat transfer will be (A) Conduction (B) Radiation (C) Natural convection (D) Forced convection

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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

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For a given ambient air temperature with increase in the thickness of insulation of a hot cylindrical pipe, the rate of heat loss from the surface would (A) Decrease(B) Increase(C) First decrease and then increase(D) First increase and then decrease

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By which of the following methods could a cup of hot coffee lose heat if placed on a metal table in a room? (a) Conduction and radiation (b) Conduction and convection (c) Convection and radiation (d) Conduction, convection, radiation and evaporation

Description : By which of the following methods could a cup of hot coffee lose heat if placed on a metal table in a room? (a) Conduction and radiation (b) Conduction and convection (c) Convection and radiation (d) Conduction, convection, radiation and evaporation

Last Answer : Ans:(d)

By what process is heat transmitted from the filament of an evacuated electric bulb to the glass? (a) Conduction (b) Convection (c) Radiation (d) Heat cannot be transmitted through vacuum

Description : By what process is heat transmitted from the filament of an evacuated electric bulb to the glass? (a) Conduction (b) Convection (c) Radiation (d) Heat cannot be transmitted through vacuum

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Transfer of heat energy from a heater coil to the cooking vessel takes place through the process of- (1) Convection only (2) Conduction and convection only (3) Radiation and convection only (4) Convection, conduction and radiation

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Description : Heat is transmitted from higher temperature to lower temperature through the actual motion of the molecules in – (1) Conduction (2) Convection (3) Radiation (4) Both conduction and convection

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Description : Heat is transmitted from higher temperature to lower temperature through the actual motion of the molecules in - (1) Conduction (2) Convection (3) Radiation (4) Both conduction and convection

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Suns heat reaches us by – (1) Conduction (2) Convection (3) Radiation (4) Reflection

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The heated parts of an electrical machine dissipate heat into their surroundings by which of the following modes of heat dissipation ? (a) Conduction (b) Convection (c) Radiation (d) All ofthe above

Description : The heated parts of an electrical machine dissipate heat into their surroundings by which of the following modes of heat dissipation ? (a) Conduction (b) Convection (c) Radiation (d) All ofthe above

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Description : In EXTRA-TERRESTRIAL SPACE, heat is transferred by: w) conduction x) convection y) conduction and convention z) radiation

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Heat is transferred from the sun to the earth primarily by: w) conduction x) convection y) radiation z) condensation

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Description : Heat is transmitted from higher temperature to lower temperature through the actual motion of the molecules in (1) Conduction (2) Convection (3) Radiation (4) Both conduction and convection

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Sun’s heat reaches us by (1) Conduction (2) Convection (3) Radiation (4) Reflection

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A thin, flat & square plate measuring 2 m × 2 m is freely hanging in ambient air at 25°C. It is exposed to the solar radiation falling on one side of the plate at the rate of 500 W/m2. The plate temperature will remain constant at 30°C, if the convective heat transfer co-efficient is __________ W/m2 °C. (A) 50 (B) 100 (C) 150 (D) 200

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Which of the following parameters is not responsible for the heat loss from a hot steam carrying bare pipe surface located in a room without fans? (A) Emissivity of pipe surface (B) Diameter & length of the pipe (C) Temperature of hot pipe surface & that of air in the room (D) None of thes

Description : Which of the following parameters is not responsible for the heat loss from a hot steam carrying bare pipe surface located in a room without fans? (A) Emissivity of pipe surface (B) Diameter & length of the pipe (C) Temperature of hot pipe surface & that of air in the room (D) None of thes

Last Answer : Option D

Upto the critical radius of insulation, added insulation, will (A) Increase the heat loss (B) Decrease heat loss and will have no effect beyond that (C) Decrease heat flux (D) Reduce convection heat loss compared to conduction heat less

Description : Upto the critical radius of insulation, added insulation, will (A) Increase the heat loss (B) Decrease heat loss and will have no effect beyond that (C) Decrease heat flux (D) Reduce convection heat loss compared to conduction heat less

Last Answer : Option B

Mode of heat transfer involved in the cooling of air cooled internal combustion engine is (A) Conduction(B) Natural convection(C) Forced convection(D) None of these

Description : Mode of heat transfer involved in the cooling of air cooled internal combustion engine is (A) Conduction (B) Natural convection (C) Forced convection (D) None of these

Last Answer : (B) Natural convection