Pick out the wrong statement. (A) In process heat exchangers, saturated steam is preferred over the superheated steam (B) The maximum is the emissive power of a surface at a temperature T1 occurs at a wavelength of λ1 . If the surface temperature is halved, the maximum in the emissive power would occur at a wavelength of 0.5 λ1 (C) When a vertical plate is heated in infinite air environmental under natural convection conditions, the velocity profile in air, normal to the plate, exhibits a maximum

Pick out the wrong statement.
(A) In process heat exchangers, saturated steam is preferred over the
superheated steam
(B) The maximum is the emissive power of a surface at a temperature
T1 occurs at a wavelength of λ1
. If the surface temperature is halved, the
maximum in the emissive power would occur at a wavelength of 0.5 λ1
(C) When a vertical plate is heated in infinite air environmental under natural
convection conditions, the velocity profile in air, normal to the plate, exhibits a
maximum
by

1 Answer

Answer :

(B) The maximum is the emissive power of a surface at a temperature
T1 occurs at a wavelength of λ1
. If the surface temperature is halved, the
maximum in the emissive power would occur at a wavelength of 0.5 λ1
by

Related questions

Pick out the wrong statement. (A) Superheated steam is preferably not used for process heating because of its low heat transfer film co-efficient (B) In a shell and tube heat exchanger, the shell pressure drop is maximum for orifice baffles (C) S.I. unit of fouling factor is Watt/m2 .°K (D) Longitudinal fins are used in extended surface heat exchangers, when the direction of fluid flow is parallel to the axis of the tube

Description : Pick out the wrong statement. (A) Superheated steam is preferably not used for process heating because of its low heat transfer film co-efficient (B) In a shell and tube heat exchanger ... surface heat exchangers, when the direction of fluid flow is parallel to the axis of the tube

Last Answer : (C) S.I. unit of fouling factor is Watt/m2 .°K

Pick out the wrong statement. (A) Economy of a multiple effect evaporator is not influenced by the boiling point elevation (B) Two identical cubes of iron and copper will have the same heat content under the same conditions of temperature (C) Double pipe heat exchangers are mostly used in the field of refrigeration (D) Finned tube heat exchangers are suitable for heating air by steam

Description : Pick out the wrong statement. (A) Economy of a multiple effect evaporator is not influenced by the boiling point elevation (B) Two identical cubes of iron and copper will have the same heat ... in the field of refrigeration (D) Finned tube heat exchangers are suitable for heating air by steam

Last Answer : (B) Two identical cubes of iron and copper will have the same heat content under the same conditions of temperature

Pick out the correct statement. (A) Higher is the temperature of the radiating body, higher is the wavelength of radiation (B) Logarithmic mean area is used for calculating the heat flow rate through a thick walled cylinder (C) The wavelength corresponding to maximum mono-chromatic emissive power increases with rise in temperature (D) Solid angle subtended by the finite surface at the radiating element is called the angle of incidence

Description : Pick out the correct statement. (A) Higher is the temperature of the radiating body, higher is the wavelength of radiation (B) Logarithmic mean area is used for calculating the heat flow rate ... ) Solid angle subtended by the finite surface at the radiating element is called the angle of incidence

Last Answer : (B) Logarithmic mean area is used for calculating the heat flow rate through a thick walled cylinder

Pick out the wrong statement. (A) In drying a solid containing moisture above the critical moisture content the number of degrees of freedom is 2 (B) Sherwood number in mass transfer corresponds to Nusselt number in heat transfer and Schmidt number to Prandtl number (C) Forced convection is relatively more effective in increasing the rate of mass transfer, if Schmidt number is larger (D) Hot gases at moderate pressure are usually in the shell side of shell and tube heat exchangers. At higher pressure, however, it is customary to put gas in the tube side

Description : Pick out the wrong statement. (A) In drying a solid containing moisture above the critical moisture content the number of degrees of freedom is 2 (B) Sherwood number in mass transfer corresponds to ... tube heat exchangers. At higher pressure, however, it is customary to put gas in the tube side

Last Answer : (C) Forced convection is relatively more effective in increasing the rate of mass transfer, if Schmidt number is larger

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

Air is to be heated by condensing steam. Two heat exchangers are available (i) a shell and tube heat exchanger and (ii) a finned tube heat exchanger. Tube side heat transfer area are equal in both the cases. The recommended arrangement is (A) Finned tube heat exchanger with air inside and steam outside (B) Finned tube heat exchanger with air outside and steam inside (C) Shell and tube heat exchanger with air inside tubes and steam on shell side (D) Shell and tube heat exchanger with air on shell side and steam inside tubes

Description : Air is to be heated by condensing steam. Two heat exchangers are available (i) a shell and tube heat exchanger and (ii) a finned tube heat exchanger. Tube side heat transfer area are equal in both ... steam on shell side (D) Shell and tube heat exchanger with air on shell side and steam inside tubes

Last Answer : (B) Finned tube heat exchanger with air outside and steam inside

Dry saturated steam can be converted into superheated steam by (A) Increasing its cross-sectional area of flow (B) Passing it through a pressure reducing valve (C) Forcing it downwards through a vertical tube (D) None of these

Description : Dry saturated steam can be converted into superheated steam by (A) Increasing its cross-sectional area of flow (B) Passing it through a pressure reducing valve (C) Forcing it downwards through a vertical tube (D) None of these

Last Answer : (B) Passing it through a pressure reducing valve

The rate of heat transfer from a vertical plate by natural convection depends upon the temperature differences (ΔT) between wall and outside bulk. The proportionality is given as (A) (ΔT) 1/4 (B) (ΔT) 1/2 (C) (ΔT) 5/4 (D) (ΔT) 3/4

Description : The rate of heat transfer from a vertical plate by natural convection depends upon the temperature differences (ΔT) between wall and outside bulk. The proportionality is given as (A) (ΔT) 1/4 (B) (ΔT) 1/2 (C) (ΔT) 5/4 (D) (ΔT) 3/4

Last Answer : (D) (ΔT) 3/4

Pick out the wrong statement. (A) The controlling resistance in case of heating of air by condensing steam is in the air film (B) The log mean temperature difference (LMTD) for counter flow and parallel flow can be theoretically same when any one of the fluids (hot or cold fluid) passes through the heat exchanger at constant temperature (C) In case of a 1 - 2 shell and tube heat exchanger, the LMTD correction factor value increases sharply, when a temperature cross occurs (D) Phase change in case of a pure fluid at a given pressure from liquid to vapor or vice-versa occurs at saturation temperature

Description : Pick out the wrong statement. (A) The controlling resistance in case of heating of air by condensing steam is in the air film (B) The log mean temperature difference (LMTD) for ... a pure fluid at a given pressure from liquid to vapor or vice-versa occurs at saturation temperature

Last Answer : (C) In case of a 1 - 2 shell and tube heat exchanger, the LMTD correction factor value increases sharply, when a temperature cross occurs

Pick out the wrong statement. (A) Fluid movement under the influence of buoyant forces resulting from change in density takes place in case of natural convection (B) The ratio NNu /NRe . Npr is called the Stanton number (C) The Peclet number is a measure of the ratio of energy transport by convection to that by conduction (D) The Colburn jH factor for heat transfer is given by Nst Npr

Description : Pick out the wrong statement. (A) Fluid movement under the influence of buoyant forces resulting from change in density takes place in case of natural convection (B) The ratio NNu /NRe . Npr is ... convection to that by conduction (D) The Colburn jH factor for heat transfer is given by Nst Npr

Last Answer : (D) The Colburn jH factor for heat transfer is given by Nst Npr

Pick out the wrong statement. (A) In case of heat transfer by purely forced convection, GR /Re 2 ≤ 1 (B) The equivalent diameter of heat transfer for a duct of square cross￾section (having each side as 'x') is equal to 4x (C) Distillation process is not the same as evaporation (D) The effectiveness of nucleate boiling depends basically on the ease with which the bubbles are formed and detached from the heating surface

Description : Pick out the wrong statement. (A) In case of heat transfer by purely forced convection, GR /Re 2 ≤ 1 (B) The equivalent diameter of heat transfer for a duct of ... nucleate boiling depends basically on the ease with which the bubbles are formed and detached from the heating surface

Last Answer : (B) The equivalent diameter of heat transfer for a duct of square cross￾section (having each side as 'x') is equal to 4x

Saturated steam at 1 atm is discharged from a turbine at 1200 kg/h. Superheated steam at 300 0C and 1 atm is needed as a feed to a heat exchanger. To produce it, the turbine discharge stream is mixed with superheated steam at 400 0C, 1 atm and specific volume of 3.11 m 3 /kg. Calculate the amount of superheated steam at 300 0C produced and the volumetric flow rate of the 400 0C steam.

Description : Saturated steam at 1 atm is discharged from a turbine at 1200 kg/h. Superheated steam at 300 0C  and 1 atm is needed as a feed to a heat exchanger. To produce it, the turbine discharge ... amount of superheated steam at 300 0C produced and the volumetric flow rate of the  400 0C steam.

Last Answer : Solution 1. Mass balance of water 1200 + m1 = m2 ………………………………………… (1) …………………….1 mark 2. Energy balance (1200 kg/h)(2676 kJ/kg) + m1(3278 kJ/kg)

Steam undergoes isentropic expansion in a turbine from 5000 kPa and 400°C (entropy = 6.65 kJ/kg K) to 150 kPa) (entropy of saturated liquid = 1.4336 kJ/kg. K, entropy of saturated vapour = 7.2234 kJ/kg. K) The exit condition of steam is (A) Superheated vapour (B) Partially condensed vapour with quality of 0.9 (C) Saturated vapour (D) Partially condensed vapour with quality of 0.1

Description : Steam undergoes isentropic expansion in a turbine from 5000 kPa and 400°C (entropy = 6.65 kJ/kg K) to 150 kPa) (entropy of saturated liquid = 1.4336 kJ/kg. K, entropy of saturated vapour = 7.2234 ... vapour with quality of 0.9 (C) Saturated vapour (D) Partially condensed vapour with quality of 0.1

Last Answer : (A) Superheated vapour

Pick out the wrong statement. (A) Biological oxygen demand (B.O.D.) value of a sewerage sample is always lower than its chemical oxygen demand (C.O.D.) value (B) Environmental pollution by NOx emission is much higher by four stroke petrol engines as compared to the two stroke engines (C) Temperature in stratosphere rises with increasing altitude (D) The characteristic of a green house body is that it allows the long wavelength incoming solar radiation to come in but does not allow the short wavelength infra red radiation to escape out of the earth's atmosphere

Description : Pick out the wrong statement. (A) Biological oxygen demand (B.O.D.) value of a sewerage sample is always lower than its chemical oxygen demand (C.O.D.) value (B) Environmental pollution by ... in but does not allow the short wavelength infra red radiation to escape out of the earth's atmosphere

Last Answer : (D) The characteristic of a green house body is that it allows the long wavelength incoming solar radiation to come in but does not allow the short wavelength infra red radiation to escape out of the earth's atmosphere

For which of the following substances, the internal energy and enthalpy are the functions of temperature only  (a) any gas  (b) saturated steam  (c) water  (d) perfect gas  (e) superheated steam.

Description : For which of the following substances, the internal energy and enthalpy are the functions of temperature only  (a) any gas  (b) saturated steam  (c) water  (d) perfect gas  (e) superheated steam.

Last Answer : Answer : d

Represent generation of steam on H-S diagram. Show constant dryness fraction lines, constant temperature lines, saturated line and superheated region on the same.

Description : Represent generation of steam on H-S diagram. Show constant dryness fraction lines, constant temperature lines, saturated line and superheated region on the same.

Last Answer : Represent generation of steam on H-S diagram. Show constant dryness fraction lines, constant temperature lines, saturated line and superheated region on the same.

Which is NOT a correct statement?  A. A superheated vapor will not condense when small amount of heat re removed  B. An ideal gas is a gas that is not a superheated vapor  C. A saturated liquid can absorb as much heat as it can without vaporizing  D. Water at 1 atm and room temperature is subcooled

Description : Which is NOT a correct statement?  A. A superheated vapor will not condense when small amount of heat re removed  B. An ideal gas is a gas that is not a superheated vapor  C. A saturated ... absorb as much heat as it can without vaporizing  D. Water at 1 atm and room temperature is subcooled

Last Answer : An ideal gas is a gas that is not a superheated vapor

Coolant present in the primary circuit of a pressurised water reactor is high pressure (A) Sub cooled water (B) Saturated water (C) Superheated steam (D) Saturated steam

Description : Coolant present in the primary circuit of a pressurised water reactor is high pressure (A) Sub cooled water (B) Saturated water (C) Superheated steam (D) Saturated steam

Last Answer : (B) Saturated wate

Which of the following approaches the ideal gas behaviour most closely? (A) Wet steam (B) Saturated steam (C) Superheated steam (D) Saturated water

Description : Which of the following approaches the ideal gas behaviour most closely? (A) Wet steam (B) Saturated steam (C) Superheated steam (D) Saturated water

Last Answer : Option C

___________________ is a vapor at the saturation conditions (saturation temperature and saturation pressure).  a) Vapor  b) Saturated Vapor  c) Superheated Vapor  d) Wet Vapor

Description : ___________________ is a vapor at the saturation conditions (saturation temperature and saturation pressure).  a) Vapor  b) Saturated Vapor  c) Superheated Vapor  d) Wet Vapor

Last Answer : Saturated Vapor

Pick out the wrong statement. (A) Packed towers are preferred for vacuum operation, because the pressure drop through the packing is less and they (packings) also lessen the possibility of tower wall collapse (B) Packed towers are preferred over plate towers for handling corrosive and foamy liquids (C) Diameter of randomly packed tower is normally more than 1.2 metres (D) Due to uneven supply and improper distribution of liquid, problem of channelling, loading & flooding is generally encountered in packed towers

Description : Pick out the wrong statement. (A) Packed towers are preferred for vacuum operation, because the pressure drop through the packing is less and they (packings) also lessen the ... of liquid, problem of channelling, loading & flooding is generally encountered in packed towers

Last Answer : (C) Diameter of randomly packed tower is normally more than 1.2 metres

Pick out the wrong statement: (A) Chemical reactions with high activation energy are very temperature sensitive (B) A flat velocity profile exists in a plug flow reactor (C) The residence time for all the elements of fluid in case of a P.F.R. need not be same (D) Half life of a reaction increases with increased initial concentration for reaction orders more than one

Description : Pick out the wrong statement: (A) Chemical reactions with high activation energy are very temperature sensitive (B) A flat velocity profile exists in a plug flow reactor (C) The residence ... D) Half life of a reaction increases with increased initial concentration for reaction orders more than one

Last Answer : (C) The residence time for all the elements of fluid in case of a P.F.R. need not be same

Saturated steam at a pressure of 25 kg/cm2is throttled to attain 5 kg/cm2. Then the outcoming steam will be (A) Wet (B) Saturated (C) Superheated (D) None of these

Description : Saturated steam at a pressure of 25 kg/cm2is throttled to attain 5 kg/cm2. Then the outcoming steam will be (A) Wet (B) Saturated (C) Superheated (D) None of these

Last Answer : C) Superheated

Air is best heated with steam in a heat exchanger of (A) Plate type (B) Double pipe type with fin on steam side (C) Double pipe type with fin on air side (D) Shell and tube type

Description : Air is best heated with steam in a heat exchanger of (A) Plate type (B) Double pipe type with fin on steam side (C) Double pipe type with fin on air side (D) Shell and tube type

Last Answer : (C) Double pipe type with fin on air side

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 35°C (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 (C) Boiling brine kept in open vessel when the bottom surface temperature of the vessel is maintained constant at 180°C (D) A sub-cooled refrigerant liquid at 8°C flowing at the rate of 6 Kg/minute through a copper pipe exposed to atmospheric air at 35°C

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

Indirect contact heat exchangers are preferred over direct contact heat exchangers, because (A) Heat transfer co-efficient are high (B) There is no risk of contamination (C) There is no mist formation (D) Cost of equipment is lower

Description : Indirect contact heat exchangers are preferred over direct contact heat exchangers, because (A) Heat transfer co-efficient are high (B) There is no risk of contamination (C) There is no mist formation (D) Cost of equipment is lower

Last Answer : (B) There is no risk of contamination

What type of steam is generated by evaporator tube of Lamont boiler ? a. Saturated steam b. Unsaturated steam c. Superheated steam d. Flash steam

Description : What type of steam is generated by evaporator tube of Lamont boiler ? a. Saturated steam b. Unsaturated steam c. Superheated steam d. Flash steam

Last Answer : a. Saturated steam

For which of the following substances, the gas laws can be used with minimum error  (a) dry steam  (b) wet steam  (c) saturated steam  (d) superheated steam  (e) steam at atmospheric pressure.

Description : For which of the following substances, the gas laws can be used with minimum error  (a) dry steam  (b) wet steam  (c) saturated steam  (d) superheated steam  (e) steam at atmospheric pressure.

Last Answer : Answer : d

LMTD for evaporators & condensers for a given terminal parameters & set of conditions for counter-flow is equal to that for parallel flow. In such heat exchangers, with one of the fluids condensing or evaporating, the surface area required is the least in the __________ flow. (A) Parallel (B) Mixed (C) Counter flow (D) Same in either 'a', b' or 'c'

Description : LMTD for evaporators & condensers for a given terminal parameters & set of conditions for counter-flow is equal to that for parallel flow. In such heat exchangers, with one of the fluids condensing or evaporating, the surface ... Parallel (B) Mixed (C) Counter flow (D) Same in either 'a', b' or 'c'

Last Answer : (D) Same in either 'a', b' or 'c'

Heat exchangers operating, when the asymptotic range is reached, (A) Provide very large heat transfer co-efficient (B) Results in making part of the heating surface inactive (C) Results in abruptly increased velocity (D) None of these

Description : Heat exchangers operating, when the asymptotic range is reached, (A) Provide very large heat transfer co-efficient (B) Results in making part of the heating surface inactive (C) Results in abruptly increased velocity (D) None of these

Last Answer : (B) Results in making part of the heating surface inactive

In case of laminar flow of fluid through a circular pipe, the (A) Shear stress over the cross-section is proportional to the distance from the surface of the pipe (B) Surface of velocity distribution is a paraboloid of revolution, whose volume equals half the volume of circumscribing cylinder (C) Velocity profile varies hyperbolically and the shear stress remains constant over the cross-section (D) Average flow occurs at a radial distance of 0.5 r from the centre of the pipe (r = pipe radius)

Description : In case of laminar flow of fluid through a circular pipe, the (A) Shear stress over the cross-section is proportional to the distance from the surface of the pipe (B) Surface of velocity distribution is a ... occurs at a radial distance of 0.5 r from the centre of the pipe (r = pipe radius)

Last Answer : (B) Surface of velocity distribution is a paraboloid of revolution, whose volume equals half the volume of circumscribing cylinder

One kilogram of water at 0°C is changed to superheated steam of one atm pressure and 300° C. The major heat consumption in the process will be to (A) Heat the water from 0°C to 100°C (B) Evaporate the water (C) To superheat the steam (D) Data insufficient, can't be predicted

Description : One kilogram of water at 0°C is changed to superheated steam of one atm pressure and 300° C. The major heat consumption in the process will be to (A) Heat the water from 0°C to 100°C (B) Evaporate the water (C) To superheat the steam (D) Data insufficient, can't be predicted

Last Answer : (B) Evaporate the water

In a co-current double pipe heat exchanger used for condensing saturated steam over the inner tube, if the entrance and exit conditions of the coolant are interchanged, then the rate of condensation will (A) Increase (B) Decrease (C) Remain unchanged (D) Either increase or decrease; depends on the coolant flow rate

Description : In a co-current double pipe heat exchanger used for condensing saturated steam over the inner tube, if the entrance and exit conditions of the coolant are interchanged, then the rate of condensation ... Decrease (C) Remain unchanged (D) Either increase or decrease; depends on the coolant flow rate

Last Answer : (C) Remain unchanged

For a given set of operating pressure limits of a Rankine cycle, the highest, efficiency occurs for [GATE-1994] (a) Saturated cycle (b) Superheated cycle (c) Reheat cycle (d) Regenerative cycle.

Description : For a given set of operating pressure limits of a Rankine cycle, the highest, efficiency occurs for [GATE-1994] (a) Saturated cycle (b) Superheated cycle (c) Reheat cycle (d) Regenerative cycle. 

Last Answer : (d) Regenerative cycle. 

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

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

Pick out the wrong statement. (A) Heat transfer by radiation cannot occur across an absolute volume (B) In case of a shell and tube heat exchanger, the pressure drop through the shell is proportional to the number of times the fluid crosses the bundle between baffles (C) Propagation velocity for travel of heat radiation through vacuum is equal to the velocity of the light (D) The amount of heat involved in the condensation or vaporisation of 1 kg of a fluid is the same

Description : Pick out the wrong statement. (A) Heat transfer by radiation cannot occur across an absolute volume (B) In case of a shell and tube heat exchanger, the pressure drop through the shell is ... The amount of heat involved in the condensation or vaporisation of 1 kg of a fluid is the same

Last Answer : (A) Heat transfer by radiation cannot occur across an absolute volume

In a heat exchanger with steam outside the tubes, a liquid gets heated to 45°C, when its flow velocity in the tubes is 2 m/s. If the flow velocity is reduced to 1 m/s, other things remaining the same, the temperature of the exit liquid will be (A) Less than 45°C (B) More than 45°C (C) Equal to 45°C (D) Initially decreases and remains constant thereafter

Description : In a heat exchanger with steam outside the tubes, a liquid gets heated to 45°C, when its flow velocity in the tubes is 2 m/s. If the flow velocity is reduced to 1 m/s, other things remaining ... than 45°C (B) More than 45°C (C) Equal to 45°C (D) Initially decreases and remains constant thereafter

Last Answer : (B) More than 45°C

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

Nusselt number is related to Grashoff number (Gr) in turbulent & laminar flow respectively, in respect of free convection over a vertical flat plate as (A) Gr0.25, Gr (B) Gr0.25, Gr0.33 (C) Gr, Gr0.25 (D) Gr0.33, Gr0.25

Description : Nusselt number is related to Grashoff number (Gr) in turbulent & laminar flow respectively, in respect of free convection over a vertical flat plate as (A) Gr0.25, Gr (B) Gr0.25, Gr0.33 (C) Gr, Gr0.25 (D) Gr0.33, Gr0.25

Last Answer : Option A

Heat transfer occurs by natural convection because change in temperature causes difference in (A) Viscosity (B) Density (C) Thermal conductivity (D) Heat capacity

Description : Heat transfer occurs by natural convection because change in temperature causes difference in (A) Viscosity (B) Density (C) Thermal conductivity (D) Heat capacity

Last Answer : (B) Density

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

How is plate heat exchangers used in an ammonia refrigeration system?

Description : How is plate heat exchangers used in an ammonia refrigeration system?

Last Answer : Plate heat exchangers are widely used in ammonia refrigeration systems, and they can be much smaller than the equivalent tubular exchanger can. They work best flooded. A flooded exchanger system ... liquid entering the exchanger, so gravity provides the driving force to circulate the refrigerant.

Pick out the wrong statement. (A) Different solids have different equilibrium moisture curves (B) Total condenser or reboiler is considered equivalent to one theoretical plate in McCabe-Thiele method of theoretical plate calculation for distillation column (C) Heat removal load on cooler remains constant, even with increase of the reflux ratio in a distillation column (D) Even a forced draft cooling tower cannot cool water below the wet bulb temperature

Description : Pick out the wrong statement. (A) Different solids have different equilibrium moisture curves (B) Total condenser or reboiler is considered equivalent to one theoretical plate in McCabe-Thiele method of ... (D) Even a forced draft cooling tower cannot cool water below the wet bulb temperature

Last Answer : (C) Heat removal load on cooler remains constant, even with increase of the reflux ratio in a distillation column

Why is a vacuum breaker used on shell and tube heat exchangers that are utilizing steam as the heating utility?

Description : Why is a vacuum breaker used on shell and tube heat exchangers that are utilizing steam as the heating utility?

Last Answer : Vacuum breakers are often installed on the shell side (steam side) of shell and tube exchangers to allow air to enter the shell in case of vacuum conditions developing inside the shell. For an ... vacuum in the shell could allow condensate to build in the unit and water hammer may result.

Pick out the wrong statement. (A) In solvent extraction, the distribution co-efficient should be as large as possible for solvent economy (B) With increase in pressure, the solubility of gases in solvent increases at a fixed temperature (C) Decrease in Murphree plate efficiency is an indication of entrainment in distillation column (D) The capacity of a distillation column is maximum at total reflux

Description : Pick out the wrong statement. (A) In solvent extraction, the distribution co-efficient should be as large as possible for solvent economy (B) With increase in pressure, the solubility of ... in distillation column (D) The capacity of a distillation column is maximum at total reflux

Last Answer : (D) The capacity of a distillation column is maximum at total reflux

Determine the amount of heat required to produce 1Kg of steam at a pressure of 7 bar, at a temperature 29 degree Celsius, under the following . (i) When the steam is wet having dryness fraction 0.87 (ii) When the steam is dry saturated Assume specific heat = 2.35KJ/KgK

Description : Determine the amount of heat required to produce 1Kg of steam at a pressure of 7 bar, at a temperature 29 degree Celsius, under the following . (i) When the steam is wet having dryness fraction 0.87 (ii) When the steam is dry saturated Assume specific heat = 2.35KJ/KgK 

Last Answer : P 7bar T 29ᵒC x=0.9 m =1kg C p =2.35 KJ/KgK At pressure 7 bar saturation Temp T sat =165 ᵒC h f =697.2 KJ/Kg h fg= 2064.8 KJ/Kg i) Heat required when steam is wet ... ) When the stem is dry saturated hg=hf+hfg =2762 kj Heat actually required = 2762-121.8 = 2640.2 kj

The atmosphere near the earth’s surface is “heated from below.” Which of the following does not significantly contribute to this heating -----------? A. Conduction of heat upward from a hot surface B. Convection from a hot surface C. Absorption of infrared energy that has been radiated from the surface D. Heat energy from the earth’s interior (Answer)

Description : The atmosphere near the earth's surface is heated from below. Which of the following does not significantly contribute to this heating -----------? A. Conduction of heat upward from a ... infrared energy that has been radiated from the surface D. Heat energy from the earth's interior (Answer)

Last Answer : D. Heat energy from the earth’s interior (Answer)

Fluid motion in the natural convection heat transfer between a solid surface and a fluid in contact with it, results from the (A) Existence of thermal boundary layer (B) Temperature gradient produced due to density difference (C) Buoyancy of the bubbles produced at active nucleation site (D) None of these

Description : Fluid motion in the natural convection heat transfer between a solid surface and a fluid in contact with it, results from the (A) Existence of thermal boundary layer (B) Temperature gradient produced ... difference (C) Buoyancy of the bubbles produced at active nucleation site (D) None of these

Last Answer : (D) None of these