398 + Mcqs in Mechanical Operations Page 2 McqOptions

51.	*$_During size reduction by a jaw crusher, the energy consumed decreases with the?
A.	Decreasing size of product at constant size of feed
B.	Decreasing machine capacity
C.	Increasing size of feed at constant reduction ratio
D.	None of these
Answer» D. None of these

Discussion

52.	*$_The most suitable equipment for the transportation of 200 mesh size particles is a?
A.	Bucket elevator
B.	Pneumatic conveyor
C.	Screw conveyor
D.	Belt conveyor
Answer» C. Screw conveyor

Discussion

53.	*$_Fick's law relates to?
A.	Energy consumption
B.	Final particle size
C.	Feed size
D.	None of these
Answer» B. Final particle size

Discussion

54.	*$_increasing the capacity of a screen __________ the screen effectiveness.?
A.	Decreases
B.	Increases
C.	Does not effect
D.	None of these
Answer» B. Increases

Discussion

55.	*$_A filter press is?
A.	A batch filter
B.	Not suitable, if the liquid is the main product
C.	Having prohibitively high maintenance cost
D.	Not suitable for wide range of materials under varying operating conditions of cake thickness and pressure
Answer» B. Not suitable, if the liquid is the main product

Discussion

56.	*$_A widely used size reduction equipment for __________ is Bradford breaker.?
A.	Talc
B.	Coal
C.	Iron core
D.	Wheat
Answer» C. Iron core

Discussion

57.	*$_In classification, particles are said to be equal settling, if they have the same terminal velocities in the?
A.	Different fluids
B.	Same fluid
C.	Same field of force
D.	Both B and C
Answer» E.

Discussion

58.	*$_Screen capacity is expressed in terms of?
A.	Tons/hr
B.	Tons/ft¬¨‚â§
C.	Both A & B
D.	Tons/hr-ft¬¨‚â§
Answer» E.

Discussion

59.	*$_Pine oil used in froth floatation technique acts as a/an?
A.	Collector
B.	Modifier
C.	Frother
D.	Activator
Answer» D. Activator

Discussion

60.	*$_Size reduction of moulding powders, waxes, resins & gums are done in a __________ mill.?
A.	Cage
B.	Hammer
C.	Both A & B
D.	Neither A nor B
Answer» D. Neither A nor B

Discussion

61.	*$___________ centrifuge is the most suitable for separation of non-friable crystals.?
A.	Tubular bowl
B.	Disc-bowl
C.	Perforated horizontal basket continuous
D.	Suspended batch basket
Answer» D. Suspended batch basket

Discussion

62.	*$_Electrical energy consumed by a jaw crusher is not a function of the?
A.	Average feed size
B.	Average product size
C.	Machine capacity
D.	None of these
Answer» E.

Discussion

63.	*$_Tube mill compared to ball mill?
A.	Produces finer products
B.	Is long in comparison with its diameter
C.	Uses smaller balls
D.	All of the above
Answer» E.

Discussion

64.	*$_Mass flow of granular solid (M) through a circular opening of dia, D follows?
A.	M ‚Äö√ √π ‚Äö√ √∂D
B.	M ‚Äö√ √π D¬¨‚â§
C.	M ‚Äö√ √π D¬¨‚â•
D.	M ‚Äö√ √π D
Answer» D. M ‚Äö√ √π D

Discussion

65.	*$_Froth floatation is the most suitable for treating?
A.	Iron ores
B.	Sulphide ores
C.	Quartzite
D.	None of these
Answer» C. Quartzite

Discussion

66.	*$_Production rate __________ with increased fineness, with a given energy input to the size reduction machine.?
A.	Decreases
B.	Increases
C.	Remains unchanged
D.	May increase or decrease; depends on the machine
Answer» B. Increases

Discussion

67.	*$_Dry powdery solid materials are transported by a __________ conveyor.?
A.	Belt
B.	Bucket
C.	Screw
D.	None of these
Answer» D. None of these

Discussion

68.	*$_In a size reduction crushing operation, feed size is 300 to 1500 mm while the product size is 100 to 300 mm. This is a case of the __________ crushing.?
A.	Secondary
B.	Fine
C.	Primary
D.	Ultrafine
Answer» D. Ultrafine

Discussion

69.	*$_A screen is said to be blinded, when the?
A.	Oversizes are present in undersize fraction
B.	Undersizes are retained in oversize fraction
C.	Screen is plugged with solid particles
D.	Screen capacity is abruptly increased
Answer» D. Screen capacity is abruptly increased

Discussion

70.	*$___________ is the most commonly used 'filter aid'.?
A.	Diatomaceous earth
B.	Fuller's earth
C.	Vermiculite
D.	Semi-plastic clay
Answer» B. Fuller's earth

Discussion

71.	*$_The study on washability of coal is done by using the __________ technique.?
A.	Tabling
B.	Elutriation
C.	Heavy media separation
D.	None of these
Answer» D. None of these

Discussion

72.	*$_In the cyclone separator used for separation of dust from dust laden gas, the gas?
A.	Enters the cyclone from the top
B.	Is admitted tangentially at high velocity
C.	Develops a helical motion inside the chamber
D.	Both B and C
Answer» E.

Discussion

73.	*$_A centrifugal filtration unit operating at a rotational speed of w has inner surface of the liquid (density ≈ì√ÖL) located at a radial distance R from the axis of rotation. The thickness of the liquid film is ≈í¬• and no cake is formed. The initial pressure drop during filtration is?
A.	¬¨Œ©w¬¨‚â§ . R¬¨‚â§ . ≈ì√ÖL
B.	¬¨Œ©w¬¨‚â§ . ≈í¬•¬¨‚â§ . ≈ì√ÖL
C.	¬¨Œ©w¬¨‚â§ . ≈í¬•≈ì√ÖL (2R + ≈í¬•)
D.	¬¨Œ©w¬¨‚â§ . R . ≈ì√ÖL(R + 2≈í¬•)
Answer» D. ¬¨Œ©w¬¨‚â§ . R . ≈ì√ÖL(R + 2≈í¬•)

Discussion

74.	*$_Which of the following conveyors cannot be recommended for transportation of abrasive materials??
A.	Belt conveyor
B.	Apron conveyor
C.	Flight conveyor
D.	Chain conveyor
Answer» D. Chain conveyor

Discussion

75.	*$_Wet seiving is employed, when the product contains __________ materials.?
A.	Abrasive
B.	Large quantity of very fine
C.	Coarse
D.	Non-sticky
Answer» C. Coarse

Discussion

76.	*$_Which of the following crushers can be considered as a combination of a jaw crusher and a roller crusher??
A.	Rod mill
B.	Fluid energy mill
C.	Gyratory crusher
D.	Ball mill
Answer» D. Ball mill

Discussion

77.	*$_What is the critical rotation speed in revolutions per second, for a ball mill of 1.2 m diameter charged with 70 mm dia balls??
A.	0.5
B.	1.0
C.	2.76
D.	0.66
Answer» E.

Discussion

78.	*$_Basic slag is not ground in?
A.	Jaw crushers
B.	Ball mills
C.	Compartment mills
D.	Tube mills
Answer» B. Ball mills

Discussion

79.	/_Which of the following is not a part of the Blake jaw crusher??
A.	Hanger
B.	Check plates
C.	Toggles
D.	Pitman
Answer» B. Check plates

Discussion

80.	/_Vacuum is applied in __________ zone, in case of a general type continuous rotary drum vacuum filter.?
A.	Filtering
B.	Washing
C.	Drying
D.	All of the above
Answer» E.

Discussion

81.	/_Maximum size reduction in a ball mill is done by the, __________ action.?
A.	Attrition
B.	Compression
C.	Impact
D.	Cutting
Answer» D. Cutting

Discussion

82.	/___________ are used for the separation of coarse particles from a slurry of fine particles.?
A.	Thickeners
B.	Classifiers
C.	Hydrocyclones
D.	Decanters
Answer» C. Hydrocyclones

Discussion

83.	/_A suspension of glass beads in ethylene glycol has a hindered settling velocity of 1.7 mm/s, while the terminal settling velocity of a single glass bead in ethylene glycol is 17 mm/s. If the Richardson-Zaki hindered settling index is 4.5, the volume fraction of solids in the suspension is?
A.	0.1
B.	0.4
C.	0.6
D.	None of these
Answer» D. None of these

Discussion

84.	/_Screen capacity is proportional to (where, S = screen aperture)?
A.	S
B.	1/S
C.	S¬¨‚â§
D.	‚Äö√ √∂S
Answer» B. 1/S

Discussion

85.	/_A belt conveyor used for the transportation of materials can?
A.	Run upto 1 km
B.	Travel at a speed upto 300 metres/minute
C.	Handle materials upto 5000 tons/hr
D.	All of the above
Answer» E.

Discussion

86.	/_The speed of a rotary drum vacuum filter may be about __________ rpm.?
A.	1
B.	50
C.	100
D.	500
Answer» B. 50

Discussion

87.	/_Which of the following gives the crushing energy required to create new surface ??
A.	Taggarts rule
B.	Fick's law
C.	Rittinger's law
D.	None of these
Answer» D. None of these

Discussion

88.	/_Ultrafine grinders operate principally by?
A.	Slow compression
B.	Impact
C.	Attrition
D.	Cutting action
Answer» D. Cutting action

Discussion

89.	/_Stamp mills are generally used for crushing?
A.	Iron ores
B.	Gold ores
C.	Talc
D.	Diamond
Answer» C. Talc

Discussion

90.	/_Separation of isotopes is generally done using a/an __________ centrifuge.?
A.	Ultra
B.	Disk-bowl
C.	Both A & B
D.	Neither A nor B
Answer» B. Disk-bowl

Discussion

91.	/_The distribution given by microscopic analysis of powder is?
A.	Number
B.	Length
C.	Area
D.	Volume
Answer» B. Length

Discussion

92.	/_Which of the following parts of a jaw crusher is subjected to maximum wear and tear during its operation??
A.	Check plates
B.	Jaw plates
C.	Toggles
D.	Crush shaft
Answer» C. Toggles

Discussion

93.	/_Laminar flow region is said to exist during agitation of a liquid in an agitator, when the value of Reynolds number is?
A.	>10
B.	<10
C.	>100
D.	<100
Answer» C. >100

Discussion

94.	/_The sphericity of a solid particle of cubical shape is?
A.	≈ì√Ñ
B.	(≈ì√Ñ/6)1/3
C.	(≈ì√Ñ/6)1/2
D.	≈ì√Ñ/3
Answer» C. (≈ì√Ñ/6)1/2

Discussion

95.	/_In continuous filtration (at a constant pressure drop), filtrate flow rate varies inversely as the?
A.	Square root of the velocity
B.	Square of the viscosity
C.	Filtration time only
D.	Washing time only
Answer» B. Square of the viscosity

Discussion

96.	/_The capacity of a classifier in 'tons of solid/hr' is given by (where, A = cross-sectional area, m¬¨‚â§ V = rising velocity of fluid, m/sec.S = percentage of solids in the suspension by volume.≈ì√Ö = density of solids, kg/m¬¨‚â•)?
A.	3.6 AVS.≈ì√Ö
B.	3.6 A.V.≈ì√Ö
C.	3.6 A.S. ≈ì√Ö
D.	3.6 AVS/≈ì√Ö
Answer» B. 3.6 A.V.≈ì√Ö

Discussion

97.	/_Sphericity of a cubical particle, when its equivalent diameter is taken as the height of the cube, is?
A.	0.5
B.	1
C.	‚Äö√ √∂2
D.	‚Äö√ √∂3
Answer» C. ‚Äö√ √∂2

Discussion

98.	/_Dust collection efficiency of electrostatic precipitator can be as high as 99.9%. Maximum temperature and pressure of dust laden gas that can be cleaned in an electrostatic precipitator is respectively.?
A.	200¬¨‚àûC and 5 atm
B.	1000¬¨‚àûC and 10 atm
C.	500¬¨‚àûC and 50 atm
D.	1000¬¨‚àûC and 500 atm
Answer» C. 500¬¨‚àûC and 50 atm

Discussion

99.	/_Capacity (in tons/hr) of jaw/gyratory crusher is equal to (where, L = length of the receiving opening, cm S = greater width of the discharge opening, cm)?
A.	0.01 L.S
B.	0.087 L.S
C.	L.S
D.	L.S/0.087
Answer» C. L.S

Discussion

100.	/_Which of the following is not a revolving/tumbling mill used for size reduction??
A.	Compartment mill
B.	Pebble mill
C.	Cage mill
D.	Rod mill
Answer» D. Rod mill

Discussion

Explore topic-wise MCQs in Chemical Engineering.

*$_During size reduction by a jaw crusher, the energy consumed decreases with the?

*$_The most suitable equipment for the transportation of 200 mesh size particles is a?

*$_Fick's law relates to?

*$_increasing the capacity of a screen __________ the screen effectiveness.?

*$_A filter press is?

*$_A widely used size reduction equipment for __________ is Bradford breaker.?

*$_In classification, particles are said to be equal settling, if they have the same terminal velocities in the?

*$_Screen capacity is expressed in terms of?

*$_Pine oil used in froth floatation technique acts as a/an?

*$_Size reduction of moulding powders, waxes, resins & gums are done in a __________ mill.?

*$___________ centrifuge is the most suitable for separation of non-friable crystals.?

*$_Electrical energy consumed by a jaw crusher is not a function of the?

*$_Tube mill compared to ball mill?

*$_Mass flow of granular solid (M) through a circular opening of dia, D follows?

*$_Froth floatation is the most suitable for treating?

*$_Production rate __________ with increased fineness, with a given energy input to the size reduction machine.?

*$_Dry powdery solid materials are transported by a __________ conveyor.?

*$_In a size reduction crushing operation, feed size is 300 to 1500 mm while the product size is 100 to 300 mm. This is a case of the __________ crushing.?

*$_A screen is said to be blinded, when the?

*$___________ is the most commonly used 'filter aid'.?

*$_The study on washability of coal is done by using the __________ technique.?

*$_In the cyclone separator used for separation of dust from dust laden gas, the gas?

*$_A centrifugal filtration unit operating at a rotational speed of w has inner surface of the liquid (density ≈ì√ÖL) located at a radial distance R from the axis of rotation. The thickness of the liquid film is ≈í¬• and no cake is formed. The initial pressure drop during filtration is?

*$_Which of the following conveyors cannot be recommended for transportation of abrasive materials??

*$_Wet seiving is employed, when the product contains __________ materials.?

*$_Which of the following crushers can be considered as a combination of a jaw crusher and a roller crusher??

*$_What is the critical rotation speed in revolutions per second, for a ball mill of 1.2 m diameter charged with 70 mm dia balls??

*$_Basic slag is not ground in?

*/*_Which of the following is not a part of the Blake jaw crusher??

*/*_Vacuum is applied in __________ zone, in case of a general type continuous rotary drum vacuum filter.?

*/*_Maximum size reduction in a ball mill is done by the, __________ action.?

*/*___________ are used for the separation of coarse particles from a slurry of fine particles.?

*/*_A suspension of glass beads in ethylene glycol has a hindered settling velocity of 1.7 mm/s, while the terminal settling velocity of a single glass bead in ethylene glycol is 17 mm/s. If the Richardson-Zaki hindered settling index is 4.5, the volume fraction of solids in the suspension is?

*/*_Screen capacity is proportional to (where, S = screen aperture)?

*/*_A belt conveyor used for the transportation of materials can?

*/*_The speed of a rotary drum vacuum filter may be about __________ rpm.?

*/*_Which of the following gives the crushing energy required to create new surface ??

*/*_Ultrafine grinders operate principally by?

*/*_Stamp mills are generally used for crushing?

*/*_Separation of isotopes is generally done using a/an __________ centrifuge.?

*/*_The distribution given by microscopic analysis of powder is?

*/*_Which of the following parts of a jaw crusher is subjected to maximum wear and tear during its operation??

*/*_Laminar flow region is said to exist during agitation of a liquid in an agitator, when the value of Reynolds number is?

*/*_The sphericity of a solid particle of cubical shape is?

*/*_In continuous filtration (at a constant pressure drop), filtrate flow rate varies inversely as the?

*/*_The capacity of a classifier in 'tons of solid/hr' is given by (where, A = cross-sectional area, m¬¨‚â§ V = rising velocity of fluid, m/sec.S = percentage of solids in the suspension by volume.≈ì√Ö = density of solids, kg/m¬¨‚â•)?

*/*_Sphericity of a cubical particle, when its equivalent diameter is taken as the height of the cube, is?

*/*_Dust collection efficiency of electrostatic precipitator can be as high as 99.9%. Maximum temperature and pressure of dust laden gas that can be cleaned in an electrostatic precipitator is respectively.?

*/*_Capacity (in tons/hr) of jaw/gyratory crusher is equal to (where, L = length of the receiving opening, cm S = greater width of the discharge opening, cm)?

*/*_Which of the following is not a revolving/tumbling mill used for size reduction??

/_Which of the following is not a part of the Blake jaw crusher??

/_Vacuum is applied in __________ zone, in case of a general type continuous rotary drum vacuum filter.?

/_Maximum size reduction in a ball mill is done by the, __________ action.?

/___________ are used for the separation of coarse particles from a slurry of fine particles.?

/_A suspension of glass beads in ethylene glycol has a hindered settling velocity of 1.7 mm/s, while the terminal settling velocity of a single glass bead in ethylene glycol is 17 mm/s. If the Richardson-Zaki hindered settling index is 4.5, the volume fraction of solids in the suspension is?

/_Screen capacity is proportional to (where, S = screen aperture)?

/_A belt conveyor used for the transportation of materials can?

/_The speed of a rotary drum vacuum filter may be about __________ rpm.?

/_Which of the following gives the crushing energy required to create new surface ??

/_Ultrafine grinders operate principally by?

/_Stamp mills are generally used for crushing?

/_Separation of isotopes is generally done using a/an __________ centrifuge.?

/_The distribution given by microscopic analysis of powder is?

/_Which of the following parts of a jaw crusher is subjected to maximum wear and tear during its operation??

/_Laminar flow region is said to exist during agitation of a liquid in an agitator, when the value of Reynolds number is?

/_The sphericity of a solid particle of cubical shape is?

/_In continuous filtration (at a constant pressure drop), filtrate flow rate varies inversely as the?

/_The capacity of a classifier in 'tons of solid/hr' is given by (where, A = cross-sectional area, m¬¨‚â§ V = rising velocity of fluid, m/sec.S = percentage of solids in the suspension by volume.≈ì√Ö = density of solids, kg/m¬¨‚â•)?

/_Sphericity of a cubical particle, when its equivalent diameter is taken as the height of the cube, is?

/_Dust collection efficiency of electrostatic precipitator can be as high as 99.9%. Maximum temperature and pressure of dust laden gas that can be cleaned in an electrostatic precipitator is respectively.?

/_Capacity (in tons/hr) of jaw/gyratory crusher is equal to (where, L = length of the receiving opening, cm S = greater width of the discharge opening, cm)?

/_Which of the following is not a revolving/tumbling mill used for size reduction??