8247 + Mcqs in Chemical Engineering Page 82 McqOptions

4051.	In case of coutte flow, the fluid flow is between two large flat parallel plates with
A.	top plate moving and the bottom plate fixed.
B.	bottom plate moving and the top plate fixed.
C.	both the plates fixed.
D.	both the plates moving.
Answer» B. bottom plate moving and the top plate fixed.

Discussion

4052.	Which of the following is not an advantage of fluidisation from transfer operation point of view?
A.	Intimate contact of the fluid with all parts of the solid particles.
B.	Lower fluid pumping power requirement.
C.	Minimisation of temperature variation.
D.	Prevention of particle seggregation.
Answer» C. Minimisation of temperature variation.

Discussion

4053.	Upto what value of 'Mach number', a fluid may be considered as incompressible ?
A.	0.03
B.	0.3
C.	3
D.	10
Answer» C. 3

Discussion

4054.	The head developed by a centrifugal pump is largely determined by the
A.	power of the pump.
B.	nature of the liquid being pumped.
C.	angle of the vanes and the speed of the tip of the impeller.
D.	vapour pressure of the liquid.
Answer» D. vapour pressure of the liquid.

Discussion

4055.	Flow rate of high velocity flue gas discharged through a stack to the atmosphere can be most conveniently measured by a
A.	pitot tube
B.	manometer
C.	rotameter
D.	none of these
Answer» B. manometer

Discussion

4056.	A rotameter works on the principle of __________ pressure drop.
A.	constant
B.	variable
C.	both (a) & (b)
D.	neither (a) nor (b)
Answer» B. variable

Discussion

4057.	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

4058.	The excess of the sum of pressure & velocity heads over the vapor pressure of the liquid at the suction is called the
A.	static submergence.
B.	net positive suction head (NPSH).
C.	cavitation sensitivity.
D.	priming.
Answer» C. cavitation sensitivity.

Discussion

4059.	A centrifugal pump designed to pump water is employed to pump a more viscous oil. In the later case, the pump
A.	develops a lower head.
B.	capacity is reduced.
C.	requires more power.
D.	all (a), (b) and (c).
Answer» E.

Discussion

4060.	In an incompressible flow of fluid, the fluid
A.	temperature remains constant.
B.	compressibility is greater than zero.
C.	density does not change with pressure & temperature.
D.	is frictionless.
Answer» D. is frictionless.

Discussion

4061.	The ratio of maximum to average velocity in case of streamline flow between parallel plates is
A.	1
B.	1.5
C.	2
D.	2.5
Answer» C. 2

Discussion

4062.	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

4063.	Pressure co-efficient is the ratio of pressure forces to __________ forces.
A.	gravity
B.	inertial
C.	viscous
D.	none of these
Answer» C. viscous

Discussion

4064.	The blades of a centrifugal impeller are said to be curved forward, if the __________ of the motion of impeller blades.
A.	inlet tip of a blade curves in a direction opposite to that
B.	outlet tip of a blade curves in a direction opposite to that
C.	inlet tip of a blade is towards the direction
D.	outlet tip of a blade is towards the direction
Answer» E.

Discussion

4065.	A floating/submerged body is always stable, if its centre of gravity
A.	lies above its centre of buoyancy.
B.	and centre of buoyancy coincide.
C.	lies below its centre of buoyancy.
D.	lies above its meta centre.
Answer» D. lies above its meta centre.

Discussion

4066.	The co-efficient of discharge of an orificemeter is a function of
A.	Reynolds number at the orifice.
B.	ratio of orifice dia to pipe dia.
C.	both (a) and (b).
D.	none of the above parameters, and has a constant value of 0.61.
Answer» D. none of the above parameters, and has a constant value of 0.61.

Discussion

4067.	What causes convective acceleration in fluid flow ?
A.	Steep slope in flow
B.	Unsteady nature of flow
C.	Non-uniformity of flow
D.	Turbulence in flow
Answer» D. Turbulence in flow

Discussion

4068.	The Stoke's stream function applies to the
A.	irrotational flow only.
B.	ideal/non-viscous fluids only.
C.	cases of axial symmetry.
D.	none of these.
Answer» D. none of these.

Discussion

4069.	Slugging in a fluidised bed can be avoided by using
A.	tall narrow vessel.
B.	deep bed of solids.
C.	shallow beds of solids and proper choice of particle size.
D.	very large particles.
Answer» D. very large particles.

Discussion

4070.	The ratio of width to depth for the most economical rectangular section in open channel flow is
A.	0.5
B.	1
C.	1.5
D.	2
Answer» E.

Discussion

4071.	The simple pitot tube measures the __________ pressure.
A.	static
B.	dynamic
C.	total
D.	none of these
Answer» D. none of these

Discussion

4072.	The line of action of the buoyant force passes through the centre of gravity of the
A.	submerged body.
B.	displaced volume of the fluid.
C.	volume of fluid vertically above the body.
D.	horizontal projection of the body.
Answer» C. volume of fluid vertically above the body.

Discussion

4073.	The friction factor for turbulent flow in a hydraulically smooth pipe
A.	depends only on Reynolds number.
B.	does not depend on Reynolds number.
C.	depends on the roughness.
D.	none of these.
Answer» B. does not depend on Reynolds number.

Discussion

4074.	The pressure at a point in a fluid is not the same in all directions, when the fluid is viscous and
A.	moving
B.	static
C.	cold
D.	hot
Answer» B. static

Discussion

4075.	Capacity of a hydraulic accumulator is defined in terms of maximum
A.	amount of energy stored.
B.	flow rate through accumulator.
C.	rate of falling of ram.
D.	volume available in the cylinder.
Answer» B. flow rate through accumulator.

Discussion

4076.	With diminishing cross-sectional area in case of subsonic flow in a converging nozzle, the
A.	velocity increases
B.	pressure decreases
C.	both (a) & (b)
D.	neither (a) nor (b)
Answer» D. neither (a) nor (b)

Discussion

4077.	Boundary layer separation is characterised by one of the conditions given below, where 'Re' is the Reynolds number for the flow. Select the appropriate conditions.
A.	Re << 1, accelerating flow
B.	Re >> 1, accelerating flow
C.	Re << 1, decelerating flow
D.	Re >>1, decelerating flow
Answer» E.

Discussion

4078.	Manometers measure the __________ pressure.
A.	vacuum as well as the atmospheric
B.	difference in
C.	absolute
D.	gage
Answer» C. absolute

Discussion

4079.	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

4080.	Piezometric head is the sum of the __________ heads.
A.	elevation & kinetic energy
B.	elevation & pressure
C.	kinetic energy & pressure
D.	none of these
Answer» C. kinetic energy & pressure

Discussion

4081.	Propellers are
A.	axial flow mixers.
B.	low speed impeller.
C.	used for mixingliquids of high viscosity.
D.	radial flow mixers.
Answer» B. low speed impeller.

Discussion

4082.	Colebrook equation for friction factor in turbulent flow is given by, . It reduces to Nikuradse equation for a value of equal to
A.	0
B.	1
C.
D.	0.5
Answer» C.

Discussion

4083.	The unit of velocity head is
A.	ft-lb/sec
B.	ft-lb/ft
C.	<sup>3</sup>
D.	ft-lbf/lb
E.	ft-lbf/sec.
Answer» D. ft-lbf/lb

Discussion

4084.	Which of the following properties of a fluid is responsible for offering resistance to shear ?
A.	Surface tension.
B.	Viscosity.
C.	Specific gravity.
D.	All (a), (b), and (c).
Answer» C. Specific gravity.

Discussion

4085.	Erosion and pits formation on the impeller of a centrifugal pump may be due to
A.	cavitation.
B.	low speed of impeller.
C.	its operation with delivery valve closed for considerable time after starting the pump.
D.	off centering of pump with motor.
Answer» B. low speed of impeller.

Discussion

4086.	Which of the following conditions must be satisfied for lift force to be developed ?
A.	The body should be bluff body.
B.	The body should be stream lined.
C.	Circulation around the body is essentially required.
D.	The main stream velocity must approach the velocity of sound in that fluid medium.
Answer» D. The main stream velocity must approach the velocity of sound in that fluid medium.

Discussion

4087.	The velocity profile exhibited by laminar flow of Newtonion fluids is such that the velocity distribution w.r.t. radius of the circular pipe is a/an __________ with the apex at the centre line of the pipe.
A.	hyperbola
B.	parabola
C.	semi-circle
D.	semi-ellipse
Answer» C. semi-circle

Discussion

4088.	With increase in the ratio of orifice diameter to pipe diameter in case of an orificemeter, the overall pressure loss
A.	decreases
B.	increases
C.	remains constant
D.	increases linearly
Answer» D. increases linearly

Discussion

4089.	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

4090.	The Mach number for hypersonic flow of compressible fluid is
A.	1
B.	> 1
C.	> 4
D.	< 2
Answer» D. < 2

Discussion

4091.	Mass velocity in case of steady flow and through a constant cross-section conduit is independent of the
A.	temperature
B.	pressure
C.	both (a) & (b)
D.	neither (a) nor (b)
Answer» D. neither (a) nor (b)

Discussion

4092.	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

4093.	f = 16/NRe, is valid for
A.	turbulent flow
B.	laminar flow through an open channel
C.	steady flow
D.	none of these
Answer» E.

Discussion

4094.	Centrifugal compressors compared to reciprocating compressors
A.	require less space.
B.	have quieter operation.
C.	have lower operating costs.
D.	all (a), (b) and (c).
Answer» E.

Discussion

4095.	For laminar flow of Newtonion fluids through a circular pipe, for a given pressure drop and length & diameter of pipe, the velocity of fluid is proportional to(where, = fluid viscosity )
A.
B.	1/
C.	<span class="root"> </span>
D.	1/
E.	<span class="root"> </span>
Answer» C. <span class="root"> </span>

Discussion

4096.	Umf is the minimum fluidisation velocity for a bed of particles. An increase in the superficial gas velocity from 2 Umf to 2.5 Umf results in (all velocities are smaller than the entrainment velocity of the particles) no change in the
A.	drag on particles
B.	drag on coloumn walls
C.	bed height
D.	bed voidage
Answer» D. bed voidage

Discussion

4097.	A mixed flow centrifugal pump
A.	employs such an impeller, through which the flow is a combination of radial & axial flow.
B.	mixes the two fluids before pumping them.
C.	pumps the two fluids separately and then mixes them.
D.	employs impellers in both the radial & axial directions.
Answer» B. mixes the two fluids before pumping them.

Discussion

4098.	In centrifugal pump operation, the cavitation can be eliminated by maintaining suction pressure __________ the vapor pressure of the liquid at the suction temperature.
A.	lower than
B.	higher than
C.	equal to
D.	none of these
Answer» C. equal to

Discussion

4099.	A bed of spherical particles (specific gravity 2.5) of uniform size 1500 m is 0.5 m in diameter and 0.5 m high. In packed bed state, the porosity may be taken as 0.4. Ergun's equation for the above fluid-particle system (in SI units) is given below : P/L = 375 x 103 VOM + 10.94 x 106 V2OM (SI units) If water is to be used as the fluidising medium, the minimum fluidisation velocity, VOM is
A.	12 mm/s
B.	16 mm/s
C.	24 mm/s
D.	28 mm/s
Answer» C. 24 mm/s

Discussion

4100.	One dimensional flow implies
A.	flow in a straight line.
B.	steady uniform flow.
C.	unsteady uniform flow.
D.	a flow which does not account for changes in transverse direction.
Answer» E.

Discussion

Explore topic-wise MCQs in Engineering.

In case of coutte flow, the fluid flow is between two large flat parallel plates with

Which of the following is not an advantage of fluidisation from transfer operation point of view?

Upto what value of 'Mach number', a fluid may be considered as incompressible ?

The head developed by a centrifugal pump is largely determined by the

Flow rate of high velocity flue gas discharged through a stack to the atmosphere can be most conveniently measured by a

A rotameter works on the principle of __________ pressure drop.

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

The excess of the sum of pressure &amp; velocity heads over the vapor pressure of the liquid at the suction is called the

A centrifugal pump designed to pump water is employed to pump a more viscous oil. In the later case, the pump

In an incompressible flow of fluid, the fluid

The ratio of maximum to average velocity in case of streamline flow between parallel plates is

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.

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

The blades of a centrifugal impeller are said to be curved forward, if the __________ of the motion of impeller blades.

A floating/submerged body is always stable, if its centre of gravity

The co-efficient of discharge of an orificemeter is a function of

What causes convective acceleration in fluid flow ?

The Stoke's stream function applies to the

Slugging in a fluidised bed can be avoided by using

The ratio of width to depth for the most economical rectangular section in open channel flow is

The simple pitot tube measures the __________ pressure.

The line of action of the buoyant force passes through the centre of gravity of the

The friction factor for turbulent flow in a hydraulically smooth pipe

The pressure at a point in a fluid is not the same in all directions, when the fluid is viscous and

Capacity of a hydraulic accumulator is defined in terms of maximum

With diminishing cross-sectional area in case of subsonic flow in a converging nozzle, the

Boundary layer separation is characterised by one of the conditions given below, where 'Re' is the Reynolds number for the flow. Select the appropriate conditions.

Manometers measure the __________ pressure.

Critical velocity in a pipe flow

Piezometric head is the sum of the __________ heads.

Propellers are

Colebrook equation for friction factor in turbulent flow is given by, . It reduces to Nikuradse equation for a value of equal to

The unit of velocity head is

Which of the following properties of a fluid is responsible for offering resistance to shear ?

Erosion and pits formation on the impeller of a centrifugal pump may be due to

Which of the following conditions must be satisfied for lift force to be developed ?

The velocity profile exhibited by laminar flow of Newtonion fluids is such that the velocity distribution w.r.t. radius of the circular pipe is a/an __________ with the apex at the centre line of the pipe.

With increase in the ratio of orifice diameter to pipe diameter in case of an orificemeter, the overall pressure loss

The vent valve provided in a liquid handling centrifugal pump is

The Mach number for hypersonic flow of compressible fluid is

Mass velocity in case of steady flow and through a constant cross-section conduit is independent of the

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

f = 16/NRe, is valid for

Centrifugal compressors compared to reciprocating compressors

For laminar flow of Newtonion fluids through a circular pipe, for a given pressure drop and length &amp; diameter of pipe, the velocity of fluid is proportional to(where, = fluid viscosity )

Umf is the minimum fluidisation velocity for a bed of particles. An increase in the superficial gas velocity from 2 Umf to 2.5 Umf results in (all velocities are smaller than the entrainment velocity of the particles) no change in the

A mixed flow centrifugal pump

In centrifugal pump operation, the cavitation can be eliminated by maintaining suction pressure __________ the vapor pressure of the liquid at the suction temperature.

One dimensional flow implies

The excess of the sum of pressure & velocity heads over the vapor pressure of the liquid at the suction is called the

For laminar flow of Newtonion fluids through a circular pipe, for a given pressure drop and length & diameter of pipe, the velocity of fluid is proportional to(where, = fluid viscosity )