34 + Mcqs in Fluid Mechanics Page 1 McqOptions

1.	The materials which have low thermal conductivity are called as
A.	thermal conductors
B.	thermal resistors
C.	thermal insulators
D.	none of the above
Answer» D. none of the above

Discussion

2.	The value of thermal conductivity k depends upon
A.	the material through which the heat is transferred
B.	the intensity of heat energy which is being transferred
C.	the area which is parallel to the heat transfer
D.	all of the above
Answer» B. the intensity of heat energy which is being transferred

Discussion

3.	What is the temperature gradient in the conduction heat transfer?
A.	change in temperature per unit change in time
B.	change in temperature per unit change in distance in the direction of heat flow
C.	change in temperature per unit change in cross-sectional area normal to the direction of heat flow
D.	change in temperature per unit change in cross-sectional area parallel to the direction of heat flow
Answer» C. change in temperature per unit change in cross-sectional area normal to the direction of heat flow

Discussion

4.	According to the Fourier's law of heat conduction, the rate of heat transfer by conduction depends upon
A.	area of cross section normal to the heat flow
B.	temperature gradient
C.	both a. and b.
D.	none of the above
Answer» D. none of the above

Discussion

5.	Which of the following dimensions is/are primary dimension/s?
A.	length (L)
B.	time (t)
C.	temperature (T)
D.	all of the above
Answer» E.

Discussion

6.	According to the Buckingham π–Theorem, the number of independent dimensionless groups, formed by combining the physical variables of a problem, is equal to
A.	[total number of physical quantities (n)] – [the number of primary dimensions (m) needed to express the dimensional formulae of n physical quantities]
B.	[the number of primary dimensions (m) needed to express the dimensional formulae of n physical quantities] – [total number of physical quantities (n)]
C.	[the number of primary dimensions (m) needed to express the dimensional formulae of n physical quantities] + [total number of physical quantities (n)]
D.	[the number of primary dimensions (m) needed to express the dimensional formulae of n physical quantities] x [total number of physical quantities (n)]
Answer» B. [the number of primary dimensions (m) needed to express the dimensional formulae of n physical quantities] – [total number of physical quantities (n)]

Discussion

7.	Why is the Buckingham π–Theorem used?
A.	to determine number of dependent dimensionless groups which are necessary to represent the phenomenon in a mathematical expression
B.	to determine number of independent dimensionless groups which are necessary to represent the phenomenon in a mathematical expression
C.	to determine number of dependent groups with their dimensions which are necessary to represent the phenomenon in a mathematical expression
D.	to determine number of independent groups with their dimensions which are necessary to represent the phenomenon in a mathematical expression
Answer» C. to determine number of dependent groups with their dimensions which are necessary to represent the phenomenon in a mathematical expression

Discussion

8.	What is/are the limitation/s of dimensional analysis for estimation of convection heat transfer coefficient
A.	it does not provide any knowledge of the mechanism
B.	it is necessary to know theoretically the variables which influence the phenomena
C.	both a. and b.
D.	none of the above
Answer» D. none of the above

Discussion

9.	Which of the following assumptions is/are correct to obtain an analytical solution for the problem on laminar boundary layer of fluid on flat plate?
A.	The fluid is incompressible
B.	The fluid is in steady-state
C.	The is not affected by fluid flow
D.	all of the above
Answer» E.

Discussion

10.	When does the general heat conduction equation which gives the temperature distribution and conduction heat flow in an isotropic solid reduce to Laplace equation?
A.	if the body or element is in unsteady-state with heat generation
B.	if the body or element is in steady-state with heat generation
C.	if the body or element is in unsteady-state with no heat generation
D.	if the body or element is in steady-state with no heat generation
Answer» E.

Discussion

11.	Consider an element with finite dimensions. In general which among the following equations is correct for change in energy of element during a time span dt?
A.	[Heat generated in the element during time dt] + [Heat flow into the element during time dt] + [Heat flow out of the element during time dt]
B.	[Heat generated in the element during time dt] + [Heat flow into the element during time dt] – [Heat flow out of the element during time dt]
C.	[Heat generated in the element during time dt] – [Heat flow into the element during time dt] – [Heat flow out of the element during time dt]
D.	none of the above
Answer» C. [Heat generated in the element during time dt] – [Heat flow into the element during time dt] – [Heat flow out of the element during time dt]

Discussion

12.	Which of the following arrangements of fins is more effective for the same base area? 1. Large number of closely spaced fins 2. Small number of thick fins
A.	Arrangement 1
B.	Arrangement 2
C.	both the arrangements 1 and 2 are similarly effective
D.	unpredictable
Answer» B. Arrangement 2

Discussion

13.	Aluminum is used as a fin material because
A.	it has higher convection heat transfer coefficient
B.	it has higher thermal conductivity
C.	it has lower convection heat transfer coefficient
D.	it has lower thermal conductivity
Answer» C. it has lower convection heat transfer coefficient

Discussion

14.	For effective working of fins, the thickness of the fines should be
A.	large
B.	small
C.	thickness of fin does not affect the fin effectiveness
D.	unpredictable
Answer» C. thickness of fin does not affect the fin effectiveness

Discussion

15.	Which medium of surrounding is better for fin effectiveness?
A.	gas medium
B.	liquid medium
C.	fins have same effectiveness in both the gas and liquid mediums
D.	none of the above
Answer» B. liquid medium

Discussion

16.	What is the effect of convective heat transfer coefficient h on fin effectiveness?
A.	fin is effective if the value of convective heat transfer coefficient h is small
B.	fin is effective if the value of convective heat transfer coefficient h is large
C.	fin effectiveness does not affected by the value of convective heat transfer coefficient h
D.	none of the above
Answer» B. fin is effective if the value of convective heat transfer coefficient h is large

Discussion

17.	What is the effect of thermal conductivity k on fin effectiveness?
A.	fin is effective for smaller value of thermal conductivity k
B.	fin is effective for larger value of thermal conductivity k
C.	thermal conductivity k does not affect the fin effectiveness
D.	cannot say
Answer» C. thermal conductivity k does not affect the fin effectiveness

Discussion

18.	What is effectiveness of fin?
A.	the ratio of actual heat transferred from fin area to the heat which would be transferred if entire fin area was at base temperature
B.	the heat which would be transferred if entire fin area was at base temperature to the ratio of actual heat transferred from fin area
C.	the heat which would be transferred if entire fin area was at minimum temperature to the ratio of actual heat transferred from fin area
D.	the ratio of actual heat transferred from fin area to the heat which would be transferred if entire fin area was at minimum temperature
Answer» B. the heat which would be transferred if entire fin area was at base temperature to the ratio of actual heat transferred from fin area

Discussion

19.	What is the relation between the rate of convection heat transfer and the rate of mixing in turbulent fluid flow?
A.	the rate of convection heat transfer decreases with increase in the rate of mixing in turbulent fluid flow
B.	the rate of convection heat transfer increases with increase in the rate of mixing in turbulent fluid flow
C.	the rate of convection heat transfer does not affected by the change in the rate of mixing in turbulent fluid flow
D.	none of the above
Answer» C. the rate of convection heat transfer does not affected by the change in the rate of mixing in turbulent fluid flow

Discussion

20.	Assume a natural convection heat transfer on a vertical flat plate surrounded by a fluid. Where will be the fully developed turbulent layer of fluid established, if the plate is hotter than the fluid?
A.	At the bottom of the plate
B.	At the middle of the plate
C.	At the top of the plate
D.	Nowhere
Answer» D. Nowhere

Discussion

21.	What is the relation between convection heat transfer coefficients of natural convection and forced convection?
A.	convection heat transfer coefficient of natural convection is lower than the convection heat transfer coefficient of forced convection
B.	convection heat transfer coefficient of natural convection is more than the convection heat transfer coefficient of forced convection
C.	convection heat transfer coefficients in both natural and forced convection are the same for same system
D.	unpredictable
Answer» B. convection heat transfer coefficient of natural convection is more than the convection heat transfer coefficient of forced convection

Discussion

22.	The intensity of mixing of fluid in natural convection is
A.	more than the intensity of mixing of fluid in forced convection
B.	less than the intensity of mixing of fluid in forced convection
C.	equal to the intensity of mixing of fluid in forced convection
D.	unpredictable
Answer» C. equal to the intensity of mixing of fluid in forced convection

Discussion

23.	The buoyancy forces which give rise to the natural convection are called as
A.	convection forces
B.	fluid forces
C.	body forces
D.	none of the above
Answer» D. none of the above

Discussion

24.	Generally, natural convection occurs due to
A.	change in velocity of a fluid
B.	change in density of a fluid
C.	change in molecular structure of a fluid
D.	none of the above
Answer» C. change in molecular structure of a fluid

Discussion

25.	The eddy properties are used in turbulent boundary layer condition because
A.	the eddy properties may be small compared to molecular properties
B.	the eddy properties may be large compared to molecular properties
C.	the eddy properties may be small or may be large compared to molecular properties, but never equals to molecular properties
D.	none of the above
Answer» C. the eddy properties may be small or may be large compared to molecular properties, but never equals to molecular properties

Discussion

26.	What is used instead of ν, in turbulent boundary layer condition?
A.	eddy diffusivity for momentum
B.	eddy diffusivity for force
C.	eddy diffusivity for heat
D.	none of the above
Answer» B. eddy diffusivity for force

Discussion

27.	The layer through which the momentum and energy transfer take place via the movement of macroscopic lumps of matter from one region to another is called as
A.	the laminar sublayer
B.	the buffer layer
C.	the turbulent layer
D.	none of the above
Answer» D. none of the above

Discussion

28.	The layer above the laminar sublayer with some turbulence and still having importance of viscous action is called as
A.	sub-sublayer
B.	turbulent layer
C.	buffer layer
D.	none of the above
Answer» D. none of the above

Discussion

29.	Assume a turbulent flow of a fluid on a flat plate. A very thin region near the plate surface is called as
A.	laminar buffer layer
B.	laminar sublayer
C.	laminar turbulent layer
D.	none of the above
Answer» C. laminar turbulent layer

Discussion

30.	Which of the following fluid can be considered as an ideal fluid?
A.	viscous fluid
B.	non-viscous fluid
C.	compressible fluid
D.	all of the above
Answer» C. compressible fluid

Discussion

31.	Viscosity of a fluid can be defined as
A.	change in density of the fluid per unit temperature
B.	flow resistance offered by the fluid
C.	flow velocity change
D.	none of the above
Answer» C. flow velocity change

Discussion

32.	What is the relation between the rate of convection heat transfer and the rate of mixing in turbulent fluid flow?
A.	the rate of convection heat transfer decreases with increase in the rate of mixing in turbulent fluid flow
B.	the rate of convection heat transfer increases with increase in the rate of mixing in turbulent fluid flow
C.	the rate of convection heat transfer does not affected by the change in the rate of mixing in turbulent fluid flow
D.	none of the above
Answer» C. the rate of convection heat transfer does not affected by the change in the rate of mixing in turbulent fluid flow

Discussion

33.	Generally, all the fluid particles in flowing fluid
A.	flow at a constant velocity
B.	flow at various velocities
C.	flow at a velocity as high as possible
D.	none of the above
Answer» C. flow at a velocity as high as possible

Discussion

34.	The fluid flow in which the fluid particles in one layer do not mix with the fluid particles in the other layer is called as
A.	laminar flow
B.	turbulent flow
C.	layer flow
D.	none of the above
Answer» B. turbulent flow

Discussion

Explore topic-wise MCQs in ENGINEERING SERVICES EXAMINATION (ESE).

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According&nbsp;to&nbsp;the&nbsp;Buckingham&nbsp;&pi;&ndash;Theorem,&nbsp;the&nbsp;number&nbsp;of&nbsp;independent&nbsp;dimensionless&nbsp;groups,&nbsp;formed&nbsp;by&nbsp;combining&nbsp;the&nbsp;physical&nbsp;variables&nbsp;of&nbsp;a&nbsp;problem,&nbsp;is&nbsp;equal&nbsp;to

Why&nbsp;is&nbsp;the&nbsp;Buckingham&nbsp;&pi;&ndash;Theorem&nbsp;used?

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When&nbsp;does&nbsp;the&nbsp;general&nbsp;heat&nbsp;conduction&nbsp;equation&nbsp;which&nbsp;gives&nbsp;the&nbsp;temperature&nbsp;distribution&nbsp;and&nbsp;conduction&nbsp;heat&nbsp;flow&nbsp;in&nbsp;an&nbsp;isotropic&nbsp;solid&nbsp;reduce&nbsp;to&nbsp;Laplace&nbsp;equation?

Consider&nbsp;an&nbsp;element&nbsp;with&nbsp;finite&nbsp;dimensions.&nbsp;In&nbsp;general&nbsp;which&nbsp;among&nbsp;the&nbsp;following&nbsp;equations&nbsp;is&nbsp;correct&nbsp;for&nbsp;change&nbsp;in&nbsp;energy&nbsp;of&nbsp;element&nbsp;during&nbsp;a&nbsp;time&nbsp;span&nbsp;dt?

Which&nbsp;of&nbsp;the&nbsp;following&nbsp;arrangements&nbsp;of&nbsp;fins&nbsp;is&nbsp;more&nbsp;effective&nbsp;for&nbsp;the&nbsp;same&nbsp;base&nbsp;area? 1.&nbsp;Large&nbsp;number&nbsp;of&nbsp;closely&nbsp;spaced&nbsp;fins 2.&nbsp;Small&nbsp;number&nbsp;of&nbsp;thick&nbsp;fins

Aluminum&nbsp;is&nbsp;used&nbsp;as&nbsp;a&nbsp;fin&nbsp;material&nbsp;because

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Which&nbsp;medium&nbsp;of&nbsp;surrounding&nbsp;is&nbsp;better&nbsp;for&nbsp;fin&nbsp;effectiveness?

What&nbsp;is&nbsp;the&nbsp;effect&nbsp;of&nbsp;convective&nbsp;heat&nbsp;transfer&nbsp;coefficient&nbsp;h&nbsp;on&nbsp;fin&nbsp;effectiveness?

What&nbsp;is&nbsp;the&nbsp;effect&nbsp;of&nbsp;thermal&nbsp;conductivity&nbsp;k&nbsp;on&nbsp;fin&nbsp;effectiveness?

What&nbsp;is&nbsp;effectiveness&nbsp;of&nbsp;fin?

&nbsp;What&nbsp;is&nbsp;the&nbsp;relation&nbsp;between&nbsp;the&nbsp;rate&nbsp;of&nbsp;convection&nbsp;heat&nbsp;transfer&nbsp;and&nbsp;the&nbsp;rate&nbsp;of&nbsp;mixing&nbsp;in&nbsp;turbulent&nbsp;fluid&nbsp;flow?

What&nbsp;is&nbsp;the&nbsp;relation&nbsp;between&nbsp;convection&nbsp;heat&nbsp;transfer&nbsp;coefficients&nbsp;of&nbsp;natural&nbsp;convection&nbsp;and&nbsp;forced&nbsp;convection?

The&nbsp;intensity&nbsp;of&nbsp;mixing&nbsp;of&nbsp;fluid&nbsp;in&nbsp;natural&nbsp;convection&nbsp;is

The&nbsp;buoyancy&nbsp;forces&nbsp;which&nbsp;give&nbsp;rise&nbsp;to&nbsp;the&nbsp;natural&nbsp;convection&nbsp;are&nbsp;called&nbsp;as

Generally,&nbsp;natural&nbsp;convection&nbsp;occurs&nbsp;due&nbsp;to

The&nbsp;eddy&nbsp;properties&nbsp;are&nbsp;used&nbsp;in&nbsp;turbulent&nbsp;boundary&nbsp;layer&nbsp;condition&nbsp;because

What&nbsp;is&nbsp;used&nbsp;instead&nbsp;of&nbsp;&nu;,&nbsp;in&nbsp;turbulent&nbsp;boundary&nbsp;layer&nbsp;condition?

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The&nbsp;layer&nbsp;above&nbsp;the&nbsp;laminar&nbsp;sublayer&nbsp;with&nbsp;some&nbsp;turbulence&nbsp;and&nbsp;still&nbsp;having&nbsp;importance&nbsp;of&nbsp;viscous&nbsp;action&nbsp;is&nbsp;called&nbsp;as

Assume&nbsp;a&nbsp;turbulent&nbsp;flow&nbsp;of&nbsp;a&nbsp;fluid&nbsp;on&nbsp;a&nbsp;flat&nbsp;plate.&nbsp;A&nbsp;very&nbsp;thin&nbsp;region&nbsp;near&nbsp;the&nbsp;plate&nbsp;surface&nbsp;is&nbsp;called&nbsp;as

Which&nbsp;of&nbsp;the&nbsp;following&nbsp;fluid&nbsp;can&nbsp;be&nbsp;considered&nbsp;as&nbsp;an&nbsp;ideal&nbsp;fluid?

Viscosity&nbsp;of&nbsp;a&nbsp;fluid&nbsp;can&nbsp;be&nbsp;defined&nbsp;as

What&nbsp;is&nbsp;the&nbsp;relation&nbsp;between&nbsp;the&nbsp;rate&nbsp;of&nbsp;convection&nbsp;heat&nbsp;transfer&nbsp;and&nbsp;the&nbsp;rate&nbsp;of&nbsp;mixing&nbsp;in&nbsp;turbulent&nbsp;fluid&nbsp;flow?

Generally,&nbsp;all&nbsp;the&nbsp;fluid&nbsp;particles&nbsp;in&nbsp;flowing&nbsp;fluid

The&nbsp;fluid&nbsp;flow&nbsp;in&nbsp;which&nbsp;the&nbsp;fluid&nbsp;particles&nbsp;in&nbsp;one&nbsp;layer&nbsp;do&nbsp;not&nbsp;mix&nbsp;with&nbsp;the&nbsp;fluid&nbsp;particles&nbsp;in&nbsp;the&nbsp;other&nbsp;layer&nbsp;is&nbsp;called&nbsp;as

The materials which have low thermal conductivity are called as

The value of thermal conductivity k depends upon

What is the temperature gradient in the conduction heat transfer?

According to the Fourier's law of heat conduction, the rate of heat transfer by conduction depends upon

Which of the following dimensions is/are primary dimension/s?

According to the Buckingham π–Theorem, the number of independent dimensionless groups, formed by combining the physical variables of a problem, is equal to

Why is the Buckingham π–Theorem used?

What is/are the limitation/s of dimensional analysis for estimation of convection heat transfer coefficient

Which of the following assumptions is/are correct to obtain an analytical solution for the problem on laminar boundary layer of fluid on flat plate?

When does the general heat conduction equation which gives the temperature distribution and conduction heat flow in an isotropic solid reduce to Laplace equation?

Consider an element with finite dimensions. In general which among the following equations is correct for change in energy of element during a time span dt?

Which of the following arrangements of fins is more effective for the same base area? 1. Large number of closely spaced fins 2. Small number of thick fins

Aluminum is used as a fin material because

For effective working of fins, the thickness of the fines should be

Which medium of surrounding is better for fin effectiveness?

What is the effect of convective heat transfer coefficient h on fin effectiveness?

What is the effect of thermal conductivity k on fin effectiveness?

What is effectiveness of fin?

What is the relation between the rate of convection heat transfer and the rate of mixing in turbulent fluid flow?

What is the relation between convection heat transfer coefficients of natural convection and forced convection?

The intensity of mixing of fluid in natural convection is

The buoyancy forces which give rise to the natural convection are called as

Generally, natural convection occurs due to

The eddy properties are used in turbulent boundary layer condition because

What is used instead of ν, in turbulent boundary layer condition?

The layer through which the momentum and energy transfer take place via the movement of macroscopic lumps of matter from one region to another is called as

The layer above the laminar sublayer with some turbulence and still having importance of viscous action is called as

Assume a turbulent flow of a fluid on a flat plate. A very thin region near the plate surface is called as

Which of the following fluid can be considered as an ideal fluid?

Viscosity of a fluid can be defined as

What is the relation between the rate of convection heat transfer and the rate of mixing in turbulent fluid flow?

Generally, all the fluid particles in flowing fluid

The fluid flow in which the fluid particles in one layer do not mix with the fluid particles in the other layer is called as