For large heat transfer area requirement, shell and tube heat exchanger is preferred, because it________________?

Is easy to operate and maintain

For condensation of pure vapors, if the heat transfer co-efficients in filmwise and drop-wise condensation are respectively hf and hd, then__________________?

hf could be greater or smaller than hd

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 ?

First decrease and then increase

First increase and then decrease

Fluid motion in the natural convection heat transfer between a solid surface and a fluid in contact with it, results from the_________________?

Existence of thermal boundary layer

Temperature gradient produced due to density difference

Buoyancy of the bubbles produced at active nucleation site

Finned tube heat exchangers__________________?

Use metal fins of low thermal conductivity

Facilitate very large temperature drop through tube wall

Film boiling is usually not desired in commercial equipments, because____________________?

The heat transfer rate is low in view of the large temperature drop

Extremely large or small volumes of fluids are generally best routed through the shell side of a shell and tube heat exchanger, because of the________________?

Flexibility possible in the baffle arrangement

High heat transfer co-efficient

Extended heat transfer surface like fins are used to increase the heat transfer rate. Fin efficiency is defined as the ratio of heat transferred across the fin surface to the theoretical heat transfer across an equal area held at the________________?

Constant temperature equal to that of the base

Evaporation by thermo compression results in the _________________________?

Realisation of multiple effect economy in a single effect

Economy of a multiple effect evaporator is not influenced much by the_______________________?

Ratio of the weight of the thin liquor to thick liquor

Double pipe heat exchangers are used__________________?

Because it occupies less floor area

When heat transfer area required is very high

When heat transfer area required is very low, i.e. (100-200 ft2).

Because it occupies less floor area

Double pipe heat exchangers are preferably useful, when____________________?

Overall heat transfer co-efficient is very high

High viscosity liquid is to be cooled

Requirement of heat transfer area is low

Overall heat transfer co-efficient is very high

A corrosive liquid is to be heated

Dittus-Boelter equation used for the determination of heat transfer co-efficient is valid ___________________?

When Grashoff number is very important

425 + Mcqs in Chemical Heat Transfer in Chemical Engineering Page 7 McqOptions

301.	For specified tube outside diameter, higher BWG means higher___________________?
A.	Tube thickness
B.	Cross-sectional area
C.	Weight per unit length
D.	None of these
Answer» C. Weight per unit length

Discussion

302.	For small temperature difference, the heat transfer rate as per Newton’s law of cooling is proportional to (where, Δt = excess temperature) ?
A.	Δt
B.	Δt2
C.	Δt3
D.	√(Δt)
Answer» B. Δt2

Discussion

303.	For shell and tube heat exchanger, with increasing heat transfer area, the purchased cost per unit heat transfer area___________________?
A.	Increases
B.	DecreasesDecreasesDecreases
C.	Remain constant
D.	Passes through a maxima
Answer» E.

Discussion

304.	For _______________ Prandtl number values, the heat conduction will be negligible in the buffer zone?
A.	Extremely low
B.	Low
C.	High
D.	No
Answer» D. No

Discussion

305.	For large heat transfer area requirement, shell and tube heat exchanger is preferred, because it________________?
A.	Occupies smaller space
B.	Is more economical
C.	Is easy to operate and maintain
D.	All A., B. and C.
Answer» E.

Discussion

306.	For hot feed, forward feeding as compared to backward feeding results in ______________ economy?
A.	Increased
B.	Decreased
C.	No effect on
D.	None of these
Answer» B. Decreased

Discussion

307.	For heat flow through very thick walled cylinder, use ___________mean radius?
A.	Arithmetic
B.	Logarithmic
C.	Geometric
D.	Either A. or C.
Answer» C. Geometric

Discussion

308.	For gases, the thermal conductivity increases with temperature rise. For liquids, with increase in concentration, its thermal conductivity generally ?
A.	Decreases
B.	Increases
C.	Remains unchanged
D.	Increases exponentially
Answer» B. Increases

Discussion

309.	For evaporation of viscous solution in a multiple effect evaporator, the preferred feeding scheme is _________________?
A.	Forward
B.	Backward
C.	Parallel
D.	None of these
Answer» C. Parallel

Discussion

310.	For condensation of pure vapors, if the heat transfer co-efficients in filmwise and drop-wise condensation are respectively hf and hd, then__________________?
A.	hf = hd
B.	hf > hd
C.	hf < hd
D.	hf could be greater or smaller than hd
Answer» D. hf could be greater or smaller than hd

Discussion

311.	For concentrating an aqueous solution of a material like anhydrous Na2SO4, whose solubility decreases with rise in temperature, the most suitable evaporator is a _______________ evaporator?
A.	High pressure
B.	Vacuum
C.	Backward feed
D.	None of these
Answer» C. Backward feed

Discussion

312.	For an ideal black body______________________?
A.	Absorptivity = 1
B.	Reflectivity = 1
C.	Emissivity = 0
D.	Transmissivity = 1
Answer» B. Reflectivity = 1

Discussion

313.	For a perfectly transparent surface (like gases), the____________________?
A.	Absorptivity = 0
B.	Transmissivity = 1
C.	Reflectivity = 0
D.	All A., B. & C.
Answer» C. Reflectivity = 0

Discussion

314.	For a multipass shell and tube heat exchanger, the LMTD correction factor is always________________?
A.	1
B.	> 1
C.	< 1
D.	Between 1 & 2
Answer» D. Between 1 & 2

Discussion

315.	For a liquid in laminar flow through a very long tube, when the exit fluid temperature approaches the wall temperature, the equation to be used is______________?
A.	Nu = 0.023 Re0.8. Pr0.4
B.	Nu = (π/2) Gz
C.	Nu = (2/π) Gz
D.	Nu = 2Gz0.5
Answer» D. Nu = 2Gz0.5

Discussion

316.	For a laminar flow of fluid in a circular tube, ‘h1’ is the convective heat transfer co-efficient at velocity ‘V1’. If the velocity is reduced by half and assuming the fluid properties are constant, the new convective heat transfer co-efficient is________________?
A.	1.26 h1
B.	0.794 h1
C.	0.574 h1
D.	1.741 h1
Answer» C. 0.574 h1

Discussion

317.	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
Answer» E.

Discussion

318.	For a fluid flowing in an annulus space, the wetted perimeter for heat transfer and pressure drop are__________________?
A.	Same
B.	Different
C.	Never different
D.	Linearly related
Answer» C. Never different

Discussion

319.	For a counter current heat exchanger with Ti h = 80°C, T°c = 60°C, T°h = 50°C and Ti c = 30°C, and the temperature difference between the two streams being the same everywhere along Z, the direction of flow of hot fluid. The temperature profile should satisfy___________________?
A.	d2T/dZ2 > 0
B.	d2T/dZ2 = 0
C.	d2T/dZ2 < 0
D.	dT/dZ = 0
Answer» C. d2T/dZ2 < 0

Discussion

320.	For a cold dilute feed to produce thick viscous liquor, backward feeding as compared to forward feeding results in_____________________?
A.	Increased economy
B.	Decreased economy
C.	Lower capacity
D.	No effect on economy
Answer» B. Decreased economy

Discussion

321.	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
Answer» E.

Discussion

322.	Finned tube heat exchangers__________________?
A.	Give larger area per tube
B.	Use metal fins of low thermal conductivity
C.	Facilitate very large temperature drop through tube wall
D.	Are used for smaller heat load
Answer» B. Use metal fins of low thermal conductivity

Discussion

323.	Film condensation is promoted on a/an _______________________ surface?
A.	Oily
B.	Coated
C.	Clean & smooth
D.	Dirty
Answer» D. Dirty

Discussion

324.	Film boiling is usually not desired in commercial equipments, because____________________?
A.	The heat transfer rate is low in view of the large temperature drop
B.	It is difficult to maintain
C.	It is not economic
D.	None of these
Answer» B. It is difficult to maintain

Discussion

325.	Film boiling occurs at ________________ pressure?
A.	Atmospheric
B.	Sub-atmospheric
C.	Negative
D.	Very high
Answer» E.

Discussion

326.	Extremely large or small volumes of fluids are generally best routed through the shell side of a shell and tube heat exchanger, because of the________________?
A.	Less corrosion problems
B.	Flexibility possible in the baffle arrangement
C.	Low pressure drop
D.	High heat transfer co-efficient
Answer» C. Low pressure drop

Discussion

327.	Extended heat transfer surface like fins are used to increase the heat transfer rate. Fin efficiency is defined as the ratio of heat transferred across the fin surface to the theoretical heat transfer across an equal area held at the________________?
A.	Surrounding temperature
B.	Average temperature of the fin
C.	Temperature of the fin end
D.	Constant temperature equal to that of the base
Answer» E.

Discussion

328.	Evaporator tubes are generally_____________________?
A.	Horizontal
B.	Vertical
C.	Inclined
D.	Random
Answer» C. Inclined

Discussion

329.	Evaporation of 1kg of water from a solution in a single effect evaporator requires about ________________ kg of steam?
A.	0.4 – 0.6
B.	1-1.3
C.	1.8-2
D.	2 – 2.4
Answer» C. 1.8-2

Discussion

330.	Evaporation by thermo compression results in the _________________________?
A.	Saving of steam
B.	Realisation of multiple effect economy in a single effect
C.	Both A. and B.
D.	None of these
Answer» D. None of these

Discussion

331.	_____________ equation relates the thermal conductivity of a solid to its temperature ?
A.	Antoine
B.	Kopp’s
C.	Lee’s
D.	Kistyakowsky
Answer» D. Kistyakowsky

Discussion

332.	Electromagnetic radiations propagate in vacuum with a velocity of _______________ metre/second?
A.	3 × 10⁵
B.	3 × 10⁸
C.	3 × 10¹⁰
D.	3 × 10¹²
Answer» C. 3 × 10¹⁰

Discussion

333.	Electro-magnetic spectrum range, which is important for radiation varies from _____________ microns?
A.	1 to 100
B.	0.5 to 50
C.	10 to 100
D.	100 to 1000
Answer» C. 10 to 100

Discussion

334.	Economy of an evaporator is influenced by the_____________________?
A.	Steam pressure
B.	Feed temperature
C.	Number of effect
D.	Both B. & C.
Answer» E.

Discussion

335.	Economy of a multiple effect evaporator is not influenced much by the_______________________?
A.	Boiling point elevations
B.	Temperature of the feed
C.	Rate of heat transfer
D.	Ratio of the weight of the thin liquor to thick liquor
Answer» B. Temperature of the feed

Discussion

336.	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.
Answer» B. Rate of heat transfer

Discussion

337.	During crystallisation, formation of crystal can occur in ______________ solution only?
A.	Saturated
B.	Supersaturated
C.	Under-saturated
D.	All A., B. and C.
Answer» C. Under-saturated

Discussion

338.	Duhring‟s rule is important in solving problems on__________________?
A.	Distillation
B.	Crystallisation
C.	Evaporation
D.	Humidification
Answer» D. Humidification

Discussion

339.	‘Duhring’s plot’ is of use in_________________?
A.	Extractive distillation
B.	Evaporation
C.	Leaching
D.	Absorption
Answer» C. Leaching

Discussion

340.	Dropwise condensation occurs on ______________ surfaces?
A.	Clean and dirt free
B.	Smooth clean
C.	Contaminated cooling
D.	Polished
Answer» D. Polished

Discussion

341.	Dropwise condensation is promoted on a/an ______________ surface?
A.	Glazed
B.	Oily
C.	Coated
D.	Smooth
Answer» C. Coated

Discussion

342.	Double pipe heat exchangers are used__________________?
A.	When heat transfer area required is very high
B.	When heat transfer area required is very low, i.e. (100-200 ft2).
C.	Because it occupies less floor area
D.	Because it is less costly
Answer» C. Because it occupies less floor area

Discussion

343.	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
Answer» C. Overall heat transfer co-efficient is very high

Discussion

344.	Dittus-Boelter equation used for the determination of heat transfer co-efficient is valid ___________________?
A.	For fluids in laminar flow
B.	For fluids in turbulent flow
C.	When Grashoff number is very important
D.	For liquid metals
Answer» C. When Grashoff number is very important

Discussion

345.	Dittus-Boelter equation cannot be used for molten metals mainly due to its very low_____________________?
A.	Prandtl number
B.	Grashoff number
C.	Thermal conductivity
D.	Viscosity
Answer» B. Grashoff number

Discussion

346.	Crystallisation of solids from a homogeneous solution is a/an ______________ process?
A.	Exothermic
B.	Mildly endothermic
C.	Highly endothermic
D.	None of these
Answer» B. Mildly endothermic

Discussion

347.	Crystal size in a continuous crystalliser depends upon the___________________?
A.	Rate of heat transfer
B.	Degree of turbulence
C.	Degree of super-saturation
D.	All A., B. and C
Answer» E.

Discussion

348.	Critical value of the _____________ number governs the transition from laminar to turbulent flow in free convection heat transfer?
A.	Grashoff
B.	Reynolds
C.	Both ‘a’ & ‘b’
D.	Prandtl & Grashoff
Answer» E.

Discussion

349.	Cpμ/K is termed as the ______________ number?
A.	Grashoff
B.	Nusselt
C.	Prandtl
D.	Stanton
Answer» D. Stanton

Discussion

350.	Corrosiveness of steam condensate is due to the presence of________________?
A.	CO2
B.	Dissolved O2
C.	Both A. & B.
D.	Neither A. nor B.
Answer» D. Neither A. nor B.

Discussion

Explore topic-wise MCQs in Chemical Engineering.

For specified tube outside diameter, higher BWG means higher___________________?

For small temperature difference, the heat transfer rate as per Newton’s law of cooling is proportional to (where, Δt = excess temperature) ?

For shell and tube heat exchanger, with increasing heat transfer area, the purchased cost per unit heat transfer area___________________?

For _______________ Prandtl number values, the heat conduction will be negligible in the buffer zone?

For large heat transfer area requirement, shell and tube heat exchanger is preferred, because it________________?

For hot feed, forward feeding as compared to backward feeding results in ______________ economy?

For heat flow through very thick walled cylinder, use ___________mean radius?

For gases, the thermal conductivity increases with temperature rise. For liquids, with increase in concentration, its thermal conductivity generally ?

For evaporation of viscous solution in a multiple effect evaporator, the preferred feeding scheme is _________________?

For condensation of pure vapors, if the heat transfer co-efficients in filmwise and drop-wise condensation are respectively hf and hd, then__________________?

For concentrating an aqueous solution of a material like anhydrous Na2SO4, whose solubility decreases with rise in temperature, the most suitable evaporator is a _______________ evaporator?

For an ideal black body______________________?

For a perfectly transparent surface (like gases), the____________________?

For a multipass shell and tube heat exchanger, the LMTD correction factor is always________________?

For a liquid in laminar flow through a very long tube, when the exit fluid temperature approaches the wall temperature, the equation to be used is______________?

For a laminar flow of fluid in a circular tube, ‘h1’ is the convective heat transfer co-efficient at velocity ‘V1’. If the velocity is reduced by half and assuming the fluid properties are constant, the new convective heat transfer co-efficient is________________?

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 ?

For a fluid flowing in an annulus space, the wetted perimeter for heat transfer and pressure drop are__________________?

For a counter current heat exchanger with Ti h = 80°C, T°c = 60°C, T°h = 50°C and Ti c = 30°C, and the temperature difference between the two streams being the same everywhere along Z, the direction of flow of hot fluid. The temperature profile should satisfy___________________?

For a cold dilute feed to produce thick viscous liquor, backward feeding as compared to forward feeding results in_____________________?

Fluid motion in the natural convection heat transfer between a solid surface and a fluid in contact with it, results from the_________________?

Finned tube heat exchangers__________________?

Film condensation is promoted on a/an _______________________ surface?

Film boiling is usually not desired in commercial equipments, because____________________?

Film boiling occurs at ________________ pressure?

Extremely large or small volumes of fluids are generally best routed through the shell side of a shell and tube heat exchanger, because of the________________?

Extended heat transfer surface like fins are used to increase the heat transfer rate. Fin efficiency is defined as the ratio of heat transferred across the fin surface to the theoretical heat transfer across an equal area held at the________________?

Evaporator tubes are generally_____________________?

Evaporation of 1kg of water from a solution in a single effect evaporator requires about ________________ kg of steam?

Evaporation by thermo compression results in the _________________________?

_____________ equation relates the thermal conductivity of a solid to its temperature ?

Electromagnetic radiations propagate in vacuum with a velocity of _______________ metre/second?

Electro-magnetic spectrum range, which is important for radiation varies from _____________ microns?

Economy of an evaporator is influenced by the_____________________?

Economy of a multiple effect evaporator is not influenced much by the_______________________?

Economy of a multiple effect evaporator depends upon the _____________________?

During crystallisation, formation of crystal can occur in ______________ solution only?

Duhring‟s rule is important in solving problems on__________________?

‘Duhring’s plot’ is of use in_________________?

Dropwise condensation occurs on ______________ surfaces?

Dropwise condensation is promoted on a/an ______________ surface?

Double pipe heat exchangers are used__________________?

Double pipe heat exchangers are preferably useful, when____________________?

Dittus-Boelter equation used for the determination of heat transfer co-efficient is valid ___________________?

Dittus-Boelter equation cannot be used for molten metals mainly due to its very low_____________________?

Crystallisation of solids from a homogeneous solution is a/an ______________ process?

Crystal size in a continuous crystalliser depends upon the___________________?

Critical value of the _____________ number governs the transition from laminar to turbulent flow in free convection heat transfer?

Cpμ/K is termed as the ______________ number?

Corrosiveness of steam condensate is due to the presence of________________?