1608 + Mcqs in Fluid Mechanics Page 24 McqOptions

1151.	Hydraulic radius is the ratio of
A.	wetted perimeter to flow area.
B.	flow area to wetted perimeter.
C.	flow area to square of wetted perimeter.
D.	square root of flow area to wetted perimeter.
Answer» C. flow area to square of wetted perimeter.

Discussion

1152.	The pressure co-efficient is the ratio of pressure forces to __________ forces.
A.	viscous
B.	inertial
C.	gravity
D.	surface tension
Answer» B. inertial

Discussion

1153.	The capacity of a centrifugal pump Can be increased by increasing the
A.	impeller diameter or speed.
B.	number of pumps and joining them in series,
C.	number of pumps and joining them in parallel.
D.	all (a), (b) and (c).
Answer» E.

Discussion

1154.	The terminal velocity of a particle moving through a fluid varies as dpn. The value of n is equal to __________ in Stoke's law regime.
A.	1
B.	0.5
C.	2
D.	1.5
Answer» D. 1.5

Discussion

1155.	The maximum head that can be developed by a single impeller is __________ ft.
A.	25
B.	100
C.	250-300
D.	1000
Answer» D. 1000

Discussion

1156.	Pressure drop (Œîp) for a fluid flowing in turbulent flow through a pipe is a function of velocity (V) as$
A.	V1.8
B.	V-0.2
C.	V2.7
D.	V2
Answer» E.

Discussion

1157.	In centrifugal pumps, cavitation occurs, when pressure of the impeller eye or vane becomes
A.	less than atmospheric pressure.
B.	more than liquid vapor pressure.
C.	less than liquid vapor pressure.
D.	more than atmospheric pressure.
Answer» D. more than atmospheric pressure.

Discussion

1158.	The equivalent diameter for pressure drop calculation for a duct of square cross-section is given by(where, x = each side of the square duct)
A.	x
B.	œÄx
C.	2x
D.	x/2
Answer» B. œÄx

Discussion

1159.	The vent valve provided in a liquid handling centrifugal pump is
A.	generally a needle valve.
B.	used to release any gases that might be vapour locking the pump.
C.	helpful in easy removal of samples.
D.	all (a), and (b) and (c).
Answer» E.

Discussion

1160.	Fanning equation is given by. It is applicable to __________ region flow.
A.	transition
B.	laminar
C.	turbulent
D.	both (b) and (c)
Answer» E.

Discussion

1161.	For an ideal fluid flow, Reynolds number is
A.	2100
B.	100
C.	0
D.	‚àû
Answer» E.

Discussion

1162.	Critical velocity in a pipe flow
A.	increases as fluid viscosity increases.
B.	increases as pipe diameter increases.
C.	independent of fluid density.
D.	none of these.
Answer» C. independent of fluid density.

Discussion

1163.	When the head pumped against is less than the head of the fluid used for pumping, the usual device is a/an
A.	ejector
B.	blower
C.	injector
D.	airlift
Answer» E.

Discussion

1164.	For the manometer set up shown in the figure, the pressure difference PA - PB is given by
A.	(œÅH - œÅair)gH
B.	(œÅH - œÅL)gH
C.	(œÅH - œÅL) gH + (œÅL - œÅair) . g(L - H)
D.	(œÅH - œÅL) gL + (œÅL - œÅair)gH
Answer» B. (œÅH - œÅL)gH

Discussion

1165.	For a given fluid flow rate, which of the following incurs maximum head loss ?
A.	Orifice meter
B.	Venturimeter
C.	Flow nozzle
D.	All of them incur the same head loss
Answer» B. Venturimeter

Discussion

1166.	A weir is used to measure the large water discharge rate from a river or from an open channel. A weir is not of __________ shape.
A.	circular
B.	rectangular
C.	triangular
D.	trapezoidal
Answer» B. rectangular

Discussion

1167.	Design of the casing of centrifugal pump should be such as to minimise the
A.	back flow through impeller
B.	loss of kinetic head
C.	loss of static head
D.	none of these
Answer» C. loss of static head

Discussion

1168.	Sewage sludge is an example of the __________ fluid.
A.	Bingham plastic
B.	Newtonion
C.	pseudoplastic
D.	dilatent
Answer» B. Newtonion

Discussion

1169.	For the production of very high vacuum, a __________ pump is normally used.
A.	diffusion
B.	centrifugal
C.	jet ejector
D.	piston
Answer» B. centrifugal

Discussion

1170.	Gear pump
A.	is a positive displacement pump.
B.	is a centrifugal pump.
C.	is a non-positive displacement pump.
D.	can be started with delivery valve closed.
Answer» B. is a centrifugal pump.

Discussion

1171.	Cd for the orifice plate varies from
A.	0.58 to 0.8
B.	0.93 to 0.98
C.	0.2 to 0.3
D.	0.02 to 0.03
Answer» B. 0.93 to 0.98

Discussion

1172.	The valve used for very remote and accurate control of fluid is a __________ valve.
A.	needle
B.	globe
C.	gate
D.	butterfly
Answer» B. globe

Discussion

1173.	Fluid flow through a packed bed is represented by the __________ equation.
A.	Fanning's
B.	Ergun's
C.	Hagen-Poiseuille's
D.	none of these
Answer» C. Hagen-Poiseuille's

Discussion

1174.	The Navier-Stokes equation deals with the law of conservation of
A.	mass
B.	energy
C.	both (a) & (b)
D.	momentum
Answer» E.

Discussion

1175.	Unit of mass velocity is
A.	kg/hr
B.	kg/m2. hr
C.	kg/m2
D.	kg/m3. hr
Answer» C. kg/m2

Discussion

1176.	While starting an axial flow pump, its delivery valve should be kept
A.	open
B.	closed
C.	either open or closed
D.	none of these
Answer» B. closed

Discussion

1177.	The discharge through a rectangular weir varies as
A.	H1/2
B.	H5/2
C.	H2/5
D.	H3/2
Answer» E.

Discussion

1178.	Which of the following equations applies to the fluid flow through a packed bed for very large Reynolds number ?
A.	Fanning equation
B.	Blake-Pllummer equation
C.	Hagen-Poiseulle equation
D.	Kozney-Karman equation
Answer» C. Hagen-Poiseulle equation

Discussion

1179.	Specific speed of a centrifugal pump relates it with another pump having the
A.	dynamic similarity
B.	same efficiency
C.	same speed
D.	geometrical similarity
Answer» B. same efficiency

Discussion

1180.	Boundary layer exists in flow
A.	of real fluids.
B.	over flat surfaces only.
C.	in pipes only.
D.	of ideal fluids only.
Answer» B. over flat surfaces only.

Discussion

1181.	Select the correct practical example of steady non-uniform flow.
A.	Motion of water around a ship in a lake.
B.	Motion of river around bridge piers.
C.	Steadily decreasing flow through a reducing section.
D.	Steadily increasing flow through a pipe.
Answer» D. Steadily increasing flow through a pipe.

Discussion

1182.	Momentum transfer in laminar flow of fluids results due to the
A.	viscosity
B.	density
C.	velocity gradient
D.	none of these
Answer» D. none of these

Discussion

1183.	The maximum depth from which a centrifugal pump can draw water is
A.	dependent on the speed of the pump.
B.	dependent on the power of the pump.
C.	34 feet.
D.	150 feet.
Answer» D. 150 feet.

Discussion

1184.	Cp/Cv is termed as
A.	adiabatic constant
B.	Mach number
C.	Weber number
D.	Prandtl number
Answer» B. Mach number

Discussion

1185.	The effect of solid boundary on the fluid flow is confined to the boundary layer, except for fluids
A.	having high viscosities.
B.	moving at low velocities.
C.	both (a) & (b).
D.	neither (a) nor (b).
Answer» D. neither (a) nor (b).

Discussion

1186.	Foot valves are provided in the suction line of a centrifugal pump to
A.	avoid priming, every time we start the pump.
B.	remove the contaminant present in the liquid.
C.	minimise the fluctuation in discharge.
D.	control the liquid discharge.
Answer» B. remove the contaminant present in the liquid.

Discussion

1187.	During ageing of fluid carrying pipes, the
A.	pipe becomes smoother with use.
B.	friction factor increases linearly with time.
C.	absolute roughness decreases with time.
D.	absolute roughness increases linearly with time.
Answer» E.

Discussion

1188.	A fluid which has a linear relationship between the magnitude of applied shear-stress and the resulting rate of deformation is called a/an __________ fluid.
A.	Newtonion
B.	Non-Newtonion
C.	ideal
D.	incompressible
Answer» B. Non-Newtonion

Discussion

1189.	Drag is the force component exerted on an immersed object,
A.	passing the centroid of the body at 60¬∞to the direction of motion.
B.	the component being parallel to theflow direction.
C.	the component being normal to the flow direction.
D.	none of these.
Answer» C. the component being normal to the flow direction.

Discussion

1190.	For the free settling of a spherical particle through a fluid, the slope of, CD-log NRe , plot is
A.	1
B.	-1
C.	0.5
D.	-0.5
Answer» C. 0.5

Discussion

1191.	I.D. of 1/4" schedule 40 pipe is 0.364". I.D. of a 1/2" schedule 40 pipe would be __________ inch
A.	4.728
B.	0.5
C.	0.622
D.	0.474
Answer» D. 0.474

Discussion

1192.	For flow through an orifice from a reservoir, the actual velocity at the vena con-tracta is given by
A.	2gh
B.	C.V. 2gh
C.	Cd 2gh
D.	Cc 2gh
Answer» C. Cd 2gh

Discussion

1193.	A compressor that takes suction at a pressure below atmospheric and discharge against atmospheric pressure is called a __________ pump.
A.	sump
B.	volute
C.	vacuum
D.	submerged
Answer» D. submerged

Discussion

1194.	A 2" gate valve fitted in a pipe is replaced by a similar globe valve. Pressure drop in gate valve was Œîp. For the same discharge, the pressure drop across globe valve is$
A.	Œîp
B.	< Œîp
C.	> Œîp
D.	Œîp2
Answer» D. Œîp2

Discussion

1195.	In parallel pipe problems, the
A.	head loss is the same through each pipe.
B.	discharge is the same through all the pipes.
C.	total head loss is equal to the sum of the head losses through each pipe.
D.	none of these.
Answer» B. discharge is the same through all the pipes.

Discussion

1196.	__________ forces act on a particle moving through a stationary fluid.
A.	Gravity
B.	Drag
C.	Buoyant
D.	all (a), (b), & (c)
Answer» E.

Discussion

1197.	What is the shear rate at the pipe wall, in case of laminar flow of Newtonion fluids in a pipe of diameter 'D' & length 'L' incurring a pressure drop 'Œîp' with average velocity 'Vavg'?$
A.	D Œîp/8L
B.	D Œîp/4L
C.	8 . Vavg/D
D.	4 . Vavg/D
Answer» D. 4 . Vavg/D

Discussion

1198.	Multistage centrifugal pumps are generally used for
A.	high head.
B.	low head but high discharge.
C.	highly viscous liquid.
D.	slurries of high solid concentration.
Answer» B. low head but high discharge.

Discussion

1199.	If 'x' is the depth of flow in an open channel of large width, then the hydraulic radius is equal to
A.	x
B.	x/2
C.	x/3
D.	2x/3
Answer» B. x/2

Discussion

1200.	The variable required to be known in correlations used for estimating the horse power of a centrifugal gas compressor and hence its cost are P. Inlet pressure Q. Compressor rpm R. Delivery pressure S. Volumetric flow rate at inlet.
A.	P, Q and R
B.	P and R
C.	R and S
D.	P, Rand S
Answer» B. P and R

Discussion

Explore topic-wise MCQs in Chemical Engineering.

Hydraulic radius is the ratio of

The pressure co-efficient is the ratio of pressure forces to __________ forces.

The capacity of a centrifugal pump Can be increased by increasing the

The terminal velocity of a particle moving through a fluid varies as dpn. The value of n is equal to __________ in Stoke's law regime.

The maximum head that can be developed by a single impeller is __________ ft.

Pressure drop (Œîp) for a fluid flowing in turbulent flow through a pipe is a function of velocity (V) as$

In centrifugal pumps, cavitation occurs, when pressure of the impeller eye or vane becomes

The equivalent diameter for pressure drop calculation for a duct of square cross-section is given by(where, x = each side of the square duct)

The vent valve provided in a liquid handling centrifugal pump is

Fanning equation is given by. It is applicable to __________ region flow.

For an ideal fluid flow, Reynolds number is

Critical velocity in a pipe flow

When the head pumped against is less than the head of the fluid used for pumping, the usual device is a/an

For the manometer set up shown in the figure, the pressure difference PA - PB is given by

For a given fluid flow rate, which of the following incurs maximum head loss ?

A weir is used to measure the large water discharge rate from a river or from an open channel. A weir is not of __________ shape.

Design of the casing of centrifugal pump should be such as to minimise the

Sewage sludge is an example of the __________ fluid.

For the production of very high vacuum, a __________ pump is normally used.

Gear pump

Cd for the orifice plate varies from

The valve used for very remote and accurate control of fluid is a __________ valve.

Fluid flow through a packed bed is represented by the __________ equation.

The Navier-Stokes equation deals with the law of conservation of

Unit of mass velocity is

While starting an axial flow pump, its delivery valve should be kept

The discharge through a rectangular weir varies as

Which of the following equations applies to the fluid flow through a packed bed for very large Reynolds number ?

Specific speed of a centrifugal pump relates it with another pump having the

Boundary layer exists in flow

Select the correct practical example of steady non-uniform flow.

Momentum transfer in laminar flow of fluids results due to the

The maximum depth from which a centrifugal pump can draw water is

Cp/Cv is termed as

The effect of solid boundary on the fluid flow is confined to the boundary layer, except for fluids

Foot valves are provided in the suction line of a centrifugal pump to

During ageing of fluid carrying pipes, the

A fluid which has a linear relationship between the magnitude of applied shear-stress and the resulting rate of deformation is called a/an __________ fluid.

Drag is the force component exerted on an immersed object,

For the free settling of a spherical particle through a fluid, the slope of, CD-log NRe , plot is

I.D. of 1/4" schedule 40 pipe is 0.364". I.D. of a 1/2" schedule 40 pipe would be __________ inch

For flow through an orifice from a reservoir, the actual velocity at the vena con-tracta is given by

A compressor that takes suction at a pressure below atmospheric and discharge against atmospheric pressure is called a __________ pump.

A 2" gate valve fitted in a pipe is replaced by a similar globe valve. Pressure drop in gate valve was Œîp. For the same discharge, the pressure drop across globe valve is$

In parallel pipe problems, the

__________ forces act on a particle moving through a stationary fluid.

What is the shear rate at the pipe wall, in case of laminar flow of Newtonion fluids in a pipe of diameter 'D' & length 'L' incurring a pressure drop 'Œîp' with average velocity 'Vavg'?$

Multistage centrifugal pumps are generally used for

If 'x' is the depth of flow in an open channel of large width, then the hydraulic radius is equal to

The variable required to be known in correlations used for estimating the horse power of a centrifugal gas compressor and hence its cost are P. Inlet pressure Q. Compressor rpm R. Delivery pressure S. Volumetric flow rate at inlet.