-Mlt & Mla Level 1 Newest Update
2024//2025 Practice Exam With Detailed
Questions And All Accurate Answers
Which wear mechanism involves a collapsing bubble to do damage?
a) Adhesive wear
b) Erosive wear
c) Cavitation wear
d) Corrosive wear
e) Delamination wear - CORRECT ANSWER 122: c
When bubbles transfer from low to high pressure zones, they implode, producing
intense pressure and surface damage (cavitation wear).
The deformation of a rolling element to carry a load is known as what?
a) Boundary lubrication
b) Hydrodynamic lubrication
c) Elastohydrodynamic lubrication
d) DE formative film lubrication
e) Mixed film lubrication - CORRECT ANSWER 123: C
It is known as elastohydrodynamic lubrication, which is a form of hydrodynamic
lubrication (full film separate ton). However, it is called elastohydrodynamic because the
mating surfaces deform elastically (slightly) to enlarge the contact area in order to carry
the load.
When should the reservoir be cleaned/flushed?
a) Every time the oil is changed
b) When the plant is in a shutdown
c) When the system fluid viscosity changes by 7% or more
d) When sludge and deposits are detected at the oil drain
e) When the breather is changed - CORRECT ANSWER 124: d
A tank should be cleaned/flushed to avoid contaminating the new oil. Sludge and other
deposits are oxidation byproducts. Some of these deposits work as pro-oxidants that
attack the antioxidant additives of the new oil, resulting in the rapid depletion of these
important additives. Consequently, the base oil will be unprotected and become
oxidized in a short period of time.
,Which of the following describes microscopic water droplets dispersed in stable
suspension in oil?
a) Dissolved water
b) Evaporative solution
c) Emulsified water
d) Free water
e) None of the above - CORRECT ANSWER 125: c
Emulsified water represents water globules in stable suspension in oil. This generally is
because of the strong bonding between oil and water molecules. Depending on oil type
and condition, some or all of the water in excess of the oil's saturation point forms a
stable emulsion that will not separate by gravity even at high temperatures.
High soot loading is managed by what additive?
a) ZDDP
b) Dispersant
c) Over-base detergent
d) AW/EP
e) Demulsifier - CORRECT ANSWER 126: b
High soot loading is controlled by dispersant additives. This type of additive is polar and
is used to disperse soot particles in order to prevent agglomeration. Dispersant
additives envelop particles and keep them divided.
The primary reason that machinery is replaced is due to:
a) Erosion
b) Accidents
c) Obsolescence
d) Surface degradation of the metal
e) Corrosion - CORRECT ANSWER: "d"
Wear is the primary cause of machinery replacement Surface degradation of the metal
includes all types of wear such as abrasion, adhesion, erosion, corrosion, etc.
Which of the following is not a lubrication regime (mode / type)?
a) Boundary
b) Elastohydrodynamic
c) Boundarydynamic
d) Hydrodynamic
e) Mixed film - CORRECT ANSWER: "c"
• Boundary lubrication is defined as that regime of lubrication in which the load is carried
by the surface asperities rather than by the lubricant
,• Elastohydrodynamic lubrication is a form of hydrodynamic lubrication (full film
separation). It is called elastohydrodynamic because the lubricated components deform
elastically due to high pressure as in antifriction bearings, gears and cams.
• Hydrodynamic lubrication is also called full film lubrication in which the load is carried
totally by the lubricant. The hydrodynamic film is a result of the relative movement of
surfaces and the viscous resistance of the lubricant
• Mixed film lubrication is a combination of full film and boundary lubrication. In this type,
the lubricant is insufficient to carry the load and provide full film separation. Some points
of contact still occur between surfaces.
Which maintenance strategy is based strictly on tasks performed at specific time
intervals?
a) Proactive
b) Predictive
c) Preventive
d) Percussive
e) Reactive - CORRECT ANSWER "c"
Preventive maintenance is time-based. Generally, this type of maintenance is not cost-
effective because parts are changed prematurely and failures occur due to late or
improper maintenance.
Condition-based maintenance:
a) is based on the condition of the equipment and the early detection of faults
b) is based on regular time-based overhauls
c) Is based on run to failure
d) is based on the condition of the oil and other root causes
e) Answers an and d - CORRECT ANSWER: "e"
Condition-based maintenance is often referred to as predictive maintenance (PdM)
where the ultimate goal is to perform maintenance activity based on early detection of
problems using periodic or continuous monitoring, Obviously, (e) is the correct answer,
while (b) and (c) represent preventive and reactive maintenance, respectively,
The Pareto Principle (80/20 Rule) states:
a) The largest beneficial effect is obtained from a critical few maintenance tasks
b) The largest beneficial effect is obtained from the (random) many maintenance tasks
c) All machines die sometime
d) All bearings live forever
e) 80 percent of the people do 20 percent of the work - CORRECT ANSWER: "a"
In general, the Pareto Principle states that, for many events, roughly 80 percent of the
effects come from 20 percent of the causes, so the correct answer is (a).
Which of the following is not a function of the lubricant?
a) Cool surfaces
, b) Separate surfaces
c) Prevent corrosion
d) Repair surfaces
e) Provide some scaling - CORRECT ANSWER: "d"
The functions of a lubricant include controlling friction and wear by separating surfaces
in addition to cooling, corrosion prevention, sealing and transmitting power in some
applications such as hydraulic systems. The correct answer is (d), as surface repair
cannot be achieved using lubricants.
Which type or form of lubrication is considered to provide a full fluid (oil) film?
a) Elastohydrodynamic
b) Solid Film
c) Boundary
d) Mixed - CORRECT ANSWER: "a"
Elastohydrodynamic lubrication is a form of hydrodynamic lubrication (full film
separation). It is called elastohydrodynamic because the lubricated components deform
classically due to high pressure.
Elastohydrodynamic lubrication (EHL) is considered to occur primarily in:
a) Piston rings and liners
b) Journal bearings
c) Rolling bearings, gears and cams
d) Slow-moving pins and bushings
c) Worm gears - CORRECT ANSWER: "c"
EHL occurs in systems where the contact area is small and the pressure is high, such
as rolling clement bearings. gears (at the pitch line) and cams. The mating surfaces
deform elastically to enlarge the contact area, which is why it is called
clastohydrodynamic lubrication.
The oil film thickness (or dynamic operating clearance) in operating bearings:
a) Cannot be determined
b) Is about 10 microns for journal bearings (although can vary considerably)
c) Is about a micron for rolling bearings
d) Is not measurable
e) Answers b&c - CORRECT ANSWER: "e"
Generally, the film thickness in a journal bearing is approximately 10 microns, while in a
rolling element bearing it is about 1 micron. This is why rolling element bearings are
more sensitive to contaminants.
Which is not a type of base oil (base stock)?
2024//2025 Practice Exam With Detailed
Questions And All Accurate Answers
Which wear mechanism involves a collapsing bubble to do damage?
a) Adhesive wear
b) Erosive wear
c) Cavitation wear
d) Corrosive wear
e) Delamination wear - CORRECT ANSWER 122: c
When bubbles transfer from low to high pressure zones, they implode, producing
intense pressure and surface damage (cavitation wear).
The deformation of a rolling element to carry a load is known as what?
a) Boundary lubrication
b) Hydrodynamic lubrication
c) Elastohydrodynamic lubrication
d) DE formative film lubrication
e) Mixed film lubrication - CORRECT ANSWER 123: C
It is known as elastohydrodynamic lubrication, which is a form of hydrodynamic
lubrication (full film separate ton). However, it is called elastohydrodynamic because the
mating surfaces deform elastically (slightly) to enlarge the contact area in order to carry
the load.
When should the reservoir be cleaned/flushed?
a) Every time the oil is changed
b) When the plant is in a shutdown
c) When the system fluid viscosity changes by 7% or more
d) When sludge and deposits are detected at the oil drain
e) When the breather is changed - CORRECT ANSWER 124: d
A tank should be cleaned/flushed to avoid contaminating the new oil. Sludge and other
deposits are oxidation byproducts. Some of these deposits work as pro-oxidants that
attack the antioxidant additives of the new oil, resulting in the rapid depletion of these
important additives. Consequently, the base oil will be unprotected and become
oxidized in a short period of time.
,Which of the following describes microscopic water droplets dispersed in stable
suspension in oil?
a) Dissolved water
b) Evaporative solution
c) Emulsified water
d) Free water
e) None of the above - CORRECT ANSWER 125: c
Emulsified water represents water globules in stable suspension in oil. This generally is
because of the strong bonding between oil and water molecules. Depending on oil type
and condition, some or all of the water in excess of the oil's saturation point forms a
stable emulsion that will not separate by gravity even at high temperatures.
High soot loading is managed by what additive?
a) ZDDP
b) Dispersant
c) Over-base detergent
d) AW/EP
e) Demulsifier - CORRECT ANSWER 126: b
High soot loading is controlled by dispersant additives. This type of additive is polar and
is used to disperse soot particles in order to prevent agglomeration. Dispersant
additives envelop particles and keep them divided.
The primary reason that machinery is replaced is due to:
a) Erosion
b) Accidents
c) Obsolescence
d) Surface degradation of the metal
e) Corrosion - CORRECT ANSWER: "d"
Wear is the primary cause of machinery replacement Surface degradation of the metal
includes all types of wear such as abrasion, adhesion, erosion, corrosion, etc.
Which of the following is not a lubrication regime (mode / type)?
a) Boundary
b) Elastohydrodynamic
c) Boundarydynamic
d) Hydrodynamic
e) Mixed film - CORRECT ANSWER: "c"
• Boundary lubrication is defined as that regime of lubrication in which the load is carried
by the surface asperities rather than by the lubricant
,• Elastohydrodynamic lubrication is a form of hydrodynamic lubrication (full film
separation). It is called elastohydrodynamic because the lubricated components deform
elastically due to high pressure as in antifriction bearings, gears and cams.
• Hydrodynamic lubrication is also called full film lubrication in which the load is carried
totally by the lubricant. The hydrodynamic film is a result of the relative movement of
surfaces and the viscous resistance of the lubricant
• Mixed film lubrication is a combination of full film and boundary lubrication. In this type,
the lubricant is insufficient to carry the load and provide full film separation. Some points
of contact still occur between surfaces.
Which maintenance strategy is based strictly on tasks performed at specific time
intervals?
a) Proactive
b) Predictive
c) Preventive
d) Percussive
e) Reactive - CORRECT ANSWER "c"
Preventive maintenance is time-based. Generally, this type of maintenance is not cost-
effective because parts are changed prematurely and failures occur due to late or
improper maintenance.
Condition-based maintenance:
a) is based on the condition of the equipment and the early detection of faults
b) is based on regular time-based overhauls
c) Is based on run to failure
d) is based on the condition of the oil and other root causes
e) Answers an and d - CORRECT ANSWER: "e"
Condition-based maintenance is often referred to as predictive maintenance (PdM)
where the ultimate goal is to perform maintenance activity based on early detection of
problems using periodic or continuous monitoring, Obviously, (e) is the correct answer,
while (b) and (c) represent preventive and reactive maintenance, respectively,
The Pareto Principle (80/20 Rule) states:
a) The largest beneficial effect is obtained from a critical few maintenance tasks
b) The largest beneficial effect is obtained from the (random) many maintenance tasks
c) All machines die sometime
d) All bearings live forever
e) 80 percent of the people do 20 percent of the work - CORRECT ANSWER: "a"
In general, the Pareto Principle states that, for many events, roughly 80 percent of the
effects come from 20 percent of the causes, so the correct answer is (a).
Which of the following is not a function of the lubricant?
a) Cool surfaces
, b) Separate surfaces
c) Prevent corrosion
d) Repair surfaces
e) Provide some scaling - CORRECT ANSWER: "d"
The functions of a lubricant include controlling friction and wear by separating surfaces
in addition to cooling, corrosion prevention, sealing and transmitting power in some
applications such as hydraulic systems. The correct answer is (d), as surface repair
cannot be achieved using lubricants.
Which type or form of lubrication is considered to provide a full fluid (oil) film?
a) Elastohydrodynamic
b) Solid Film
c) Boundary
d) Mixed - CORRECT ANSWER: "a"
Elastohydrodynamic lubrication is a form of hydrodynamic lubrication (full film
separation). It is called elastohydrodynamic because the lubricated components deform
classically due to high pressure.
Elastohydrodynamic lubrication (EHL) is considered to occur primarily in:
a) Piston rings and liners
b) Journal bearings
c) Rolling bearings, gears and cams
d) Slow-moving pins and bushings
c) Worm gears - CORRECT ANSWER: "c"
EHL occurs in systems where the contact area is small and the pressure is high, such
as rolling clement bearings. gears (at the pitch line) and cams. The mating surfaces
deform elastically to enlarge the contact area, which is why it is called
clastohydrodynamic lubrication.
The oil film thickness (or dynamic operating clearance) in operating bearings:
a) Cannot be determined
b) Is about 10 microns for journal bearings (although can vary considerably)
c) Is about a micron for rolling bearings
d) Is not measurable
e) Answers b&c - CORRECT ANSWER: "e"
Generally, the film thickness in a journal bearing is approximately 10 microns, while in a
rolling element bearing it is about 1 micron. This is why rolling element bearings are
more sensitive to contaminants.
Which is not a type of base oil (base stock)?
