Tribology (MCQ : MODULE - 6)


Question 1: The function of bearing is to

A.Support load.
B. Transmit power.
C. Convert rotary to reciprocating motion.
D. All of the above.

(A)
(B)
(C)
(D)

Question 2: On the basis of direction of load bearing can be classified as

A. Radial, thrust, conical.
B. Radial, conical, hydrodynamic.
C. Aerodynamic, hydrodynamic, dry.
D. Rolling, sliding, linear.

(A)
(B)
(C)
(D)

Question 3: Which of the following is/are the cause of bearing failure?

A. Sudden rise in bearing load.
B. Inappropriate bearing selection.
C. Improper mounting of bearing.
D. All of above.

(A)
(B)
(C)
(D)

Question 4: Which of the following is NOT a component of ball bearing?

A. Inner ring.
B. Outer ring.
C. Balls and cage.
D. Bush.

(A)
(B)
(C)
(D)

Question 5: The rolling element that can be used in a bearing is/are:

A. Balls.
B. Needle rollers.
C. Rollers.
D. All of above.

(A)
(B)
(C)
(D)

Question 6: In a radial rolling element bearing, on increasing the size of the rolling elements would

A. Increase load capacity of the radial bearing.
B. Decrease load bearing capacity.
C. Increase or decrease depending on the constraint on outer diameter of outer ring.
D. Increase or decrease depending on the constraint on bore diameter of inner ring.

(A)
(B)
(C)
(D)

Question 7: Which of the following statements are true about the seals used in bearings?

A. Seals are made of elastic rubber.
B. Seals provide very good grease retainability.
C. A seal does not allow dust to enter.
D. All of above.

(A)
(B)
(C)
(D)

Question 8: Rolling bearings having contact angle lesser than 450 are referred as:

A. Radial bearings.
B. Axial bearings.
C. Thrust bearings.
D. Contact angle has nothing to do with axial and radial load bearing capacity.

(A)
(B)
(C)
(D)

Question 9: Lundberg palmgren approach is used to estimate:

A. Thrust load rating of bearings.
B. Static load rating of bearings.
C. Wear rate of rolling elements.
D. Life of rolling element bearings.

(A)
(B)
(C)
(D)

Question 10: In general which one of the following bearings has the highest coefficient of friction?

A. Self-aligning ball bearing.
B. Cylindrical ball bearing.
C. Thrust ball bearing.
D. Needle bearing.

(A)
(B)
(C)
(D)

Question 11: Coefficient of friction is higher for needle bearing because

A. Greater length of rollers and low manufacturing accuracy.
B. Rollers cannot be guided well.
C. Rubbing action against rollers.
D. All of above.

(A)
(B)
(C)
(D)

Question 12: Friction in rolling bearings occurs due to:

A. Loading and unloading of rolling elements on rings.
B. Deformation of rolling elements.
C. Lubricant shearing inside the bearing.
D. All of the above.

(A)
(B)
(C)
(D)

Question 13: What is/are the sources of friction inside the bearing?

A. Friction due to load.
B. Friction due to sliding.
C. Friction due to churning action of the load.
D. All of the above.

(A)
(B)
(C)
(D)

Question 14: On what factors the load capacity of a bearing depends?

A. Operational speed of the bearing and contact angle.
B. Lubricant behaviour.
C. Material properties of rings and rolling elements.
D. All of the above.

(A)
(B)
(C)
(D)

Question 15: What is meant by the preloading of the bearings?

A. Extra load apart from the rated load capacity.
B. Initial load on the bearings before the start of the operations.
C. Negative clearance between rolling elements and bearing rings.
D. All of the above.

(A)
(B)
(C)
(D)

Question 16: Bearing misalignment is:

A. Deformation of rolling elements.
B. Wear of rolling elements.
C. Angle greater than 0.50 between axes of inner and outer rings.
D. All of the above.

(A)
(B)
(C)
(D)

Question 17: Which of the following is NOT a common value of pressure angle used in gears?

A. 14.50.
B. 200.
C. 20.50.
D. 250.

(A)
(B)
(C)
(D)

Question 18: Which one is the advantage of helical gear over spur gear?

A. Silent operation.
B. Power transmission between non parallel shafts.
C. Decreased tooth loading.
D. All of above.

(A)
(B)
(C)
(D)

Question 19: How is herringbone gear better than the helical gear?

A. Side thrust on one half is balanced by the other half.
B. Use of substantial thrust bearing can be avoided.
C. Both (a) & (b).
D. Herringbone gears easier to manufacture compare to helical gears.

(A)
(B)
(C)
(D)

Question 20: Commonly used mechanisms for gear lubrication are:

A. Splash lubrication.
B. Pressurized lubrication by oil jets.
C. Both (a) & (b).
D. Hydrodynamic pressure.

(A)
(B)
(C)
(D)

Question 21: Required material properties for the design of journal bearing are:

A. Durable.
B. Low friction.
C. Low wear.
D. All of the above.

(A)
(B)
(C)
(D)

Question 22: With respect to journal bearing, increasing bearing length would

A. Increase load bearing capacity.
B. Decrease load bearing capacity.
C. First increases and then decreases load bearing capacity.
D. First decreases and then increases load bearing capacity.

(A)
(B)
(C)
(D)

Question 23: What are very important factors for design of hydrodynamic bearing for given shaft diameter?

A. Bearing clearance, length.
B. Bearing length, bore diameter.
C. Both (a) & (b).
D. Bearing thickness.

(A)
(B)
(C)
(D)

Question 24: How many rolling elements are present inside a hydrodynamic bearing?

A. 10
B. 12.
C. 15.
D. None of these.

(A)
(B)
(C)
(D)

Question 25: In what operating conditions grease is used to lubricate a journal bearing?

A. Temperature involved is low.
B. Low operating speed.
C. Both (a) & (b).
D. None of these.

(A)
(B)
(C)
(D)

Question 26: The purpose of self-aligning bearing is to

A. toleratea small amount of misalignment between the axes of shaft and bearing.
B. Toleratea small amount of wear in the rolling elements for continuous operation.
C. Tolerate the plastic deformation in rolling elements and cage.
D. Tolerate a small amount of temperature variation.

(A)
(B)
(C)
(D)

Question 27: Static load capacity of radial rolling bearings is defined as

A. The load acting on the bearing when the rolling elements are not experiencing any load.
B. The load acting on the bearing when there is no plastic deformation on the rolling elements.
C. The load acting on the bearing when the shaft is stationary.
D. The load that produces a total permanent deformation of rolling element and raceway, which is approximately 0.01% of the rolling element diameter.

(A)
(B)
(C)
(D)

Question 28: The two commonly used grades of porous bearings are:

A. Copper base.
B. Iron base.
C. Both (a) & (b).
D. None of the above.

(A)
(B)
(C)
(D)

Question 29: The life of the bearing is estimated in

A. Number of revolutions at some constant speed.
B. Numbers of hours of service at some constant speed.
C. Both (a) & (b).
D. None of these.

(A)
(B)
(C)
(D)

Question 30: In taper roller bearings the inner and outer rings are known as

A. Cone and cup respectively.
B. Cup and cone respectively.
C. Cone 1 and Cone 2 respectively.
D. Cup 1 and Cup 2 respectively.

(A)
(B)
(C)
(D)

Question 31: Weibull distribution represents the relationship between

A. Bearing life and reliability.
B. Bearing life and load bearing capacity.
C. Static and dynamics load capacities of the bearings.
D. Number of rolling elements and load capacity.

(A)
(B)
(C)
(D)

Question 32: Which one of the following is NOT the function of bearing?

A. Ensure free rotation of the shaft with minimum friction.
B. Support the shaft and hold it in correct position.
C. Take up forces that act on shaft and transmit them to the frame or foundation.
D. Reduce centrifugal force of the shaft.

(A)
(B)
(C)
(D)

Question 33: Which one of the following is an example of antifriction bearing?

A. Journal bearing.
B. Plain bearing.
C. Thrust rolling bearing.
D. Sleeve bearing.

(A)
(B)
(C)
(D)

Question 34: Disadvantage(s) of cylindrical bearing is/are:

A. Cylindrical roller bearing is more rigid than ball bearing.
B. Cylindrical roller bearing generates more noise.
C. Cylindrical roller bearing is not self-aligning.
D. Both (b) & (c).

(A)
(B)
(C)
(D)

Question 35: Unique advantage(s) of deep groove ball bearing is/are:

A. High load carry capacity due to relatively large size of the balls.
B. Ability to take load in radial and axial direction.
C. Performance in high speed applications due to less frictional loss.
D. All of the above.

(A)
(B)
(C)
(D)

Question 36: Which one of the following bearing is most appropriate for household applications where noise is an important consideration?

A. Deep groove ball bearing.
B. Self-aligning ball bearings.
C. Roller bearings.
D. Needle roller bearing.

(A)
(B)
(C)
(D)

Question 37: Babbitt is called a white metal because of:

A. Its whitish appearance.
B. Its silvery appearance.
C. Its highly reflective surface.
D. Its tin content.

(A)
(B)
(C)
(D)

Question 38: The factors that constitute energy loss in hydrostatic bearing are:

A. Energy lost to pump the lubricating oil.
B. Energy lost due to viscous friction.
C. Both (a) & (b).
D. None of these.

(A)
(B)
(C)
(D)

Question 39: Which of the following is true about full journal bearing?

A. The angle of contact of bushing with the journal is 3600.
B. The angle of contact of bushing with the journal is less than 1800.
C. Full journal bearing can take load in any axial direction.
D. Full journal bearing can take load in any radial direction.

(A)
(B)
(C)
(D)

Question 40: With reference to journal bearing, clearance bearing is one in which

A. Radius of the journal is more than the radius of the bearing.
B. Radius of the journal is lesser than the radius of the bearing.
C. Length of the journal is more than the radius of the bearing.
D. Length of the journal is lesser than the radius of the bearing.

(A)
(B)
(C)
(D)

Question 41: Popular bearing material Babbitt is an alloy of:

A. Tin, aluminium, copper, and antimony.
B. Tin, lead, copper, and antimony.
C. Manganese, lead, copper, and antimony.
D. Molybdenum, lead, copper, and antimony.

(A)
(B)
(C)
(D)

Question 42: Which of the following non-metals can be used as bearing materials?

A. Graphite.
B. Plastics(Teflon).
C. Rubber.
D. All of above.

(A)
(B)
(C)
(D)

Question 43: Velocity ratio or speed ratio with respect to gears is the ratio between:

A. Angular velocity of the driving gear to the angular velocity of the driven gear.
B. Angular velocity of the driven gear to the angular velocity of the driving gear.
C. Tangential velocity of the driving gear to the tangential velocity of the driven gear.
D. Tangential velocity of the drivengear to the tangential velocity of the drivinggear.

(A)
(B)
(C)
(D)

Question 44: Worm gear is used to transmit power between:

A. Two non-intersecting shafts generally at right angles to each other.
B. Inclined shafts generally at acute angle to each other.
C. Parallel shafts which are at close distance to each other.
D. Parallel shafts which are at significant distance from each other.

(A)
(B)
(C)
(D)

Question 45: For heavy radial loads and large shaft diameters which is the most appropriate bearing from the following bearing types?

A. Ball bearing.
B. Roller bearing.
C. Self-aligning bearing.
D. Needle roller bearing.

(A)
(B)
(C)
(D)

Question 46: Which of the following represents the correct sequence of bearing selection from manufacturer’s catalogue?

STEP 1: Calculations of radial and axial forces and determining the diameter of the shaft where the bearing is to be fitted.

STEP 2: Determining the type of bearing for the given application.

STEP 3: Determining the values of radial and thrust factors from the catalogue.

STEP 4: Calculation of equivalent dynamic load and estimating bearing life in million revolutions.

STEP 5: Calculation of dynamic load capacity and verifying the dynamic load capacity of the bearing.

A. STEP 1, STEP 2, STEP 3, STEP 5, STEP 4.
B. STEP 1, STEP 3, STEP 2, STEP 4, STEP 5.
C. STEP 1, STEP 2, STEP 3, STEP 4, STEP 5.
D. STEP 2, STEP 1, STEP 3, STEP 5, STEP 4.

(A)
(B)
(C)
(D)

Question 47: The two basic patterns of oil grooves used in bearings are:

A. Circumferential groove.
B. Axial groove.
C. Both (a) and (b).
D. Symmetrical groove.

(A)
(B)
(C)
(D)

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