Reference no: EM13717233

1. The viscosity index,

a) is a measure of oil viscosity that ranges between 0 and 100;

b) is higher for lubricants exhibiting greater change of viscosity with changing temperature;

c) is negative for engine oils exhibiting increasing viscosity with increasing temperature;

d) is higher for oils exhibiting less change of viscosity with changing temperature.

2. A base oil

a) is the minor component of an oil-based lubricant;

b) is an oil additive that counteracts oil acidity arising from oil degradation;

c) can be mineral, synthetic or biological in origin and constitutes the major component of a lubricant;

d) is a reference oil used for baseline comparisons.

3. Which one of the following is classed as a metal detergent typically used in engine oils?

a) Zinc dialkyldithiophosphate;

b) Calcium salicyclate;

c) Molybdenum disulfide;

d) Lauric acid.

4. Viscosity increase of engine oils during service is most likely to be caused by,

a) fuel contamination;

b) additive reaction;

c) oil oxidation;

d) dust contamination.

5. Which NLGI class grease would be considered most suitable for lubricating the components of a conveyor station using an automatic centralised lubrication system,

a) 000;

b) 1;

c) 5;

d) 10.  

6. Hydrodynamic lubrication requires

a) a converging film profile;

b) an inviscid fluid;

c) a negative entraining velocity;

d) all of the above.

7. For a narrow journal bearing, an eccentricity ratio of about 0.7,

a) gives maximum bearing load carrying capacity;

b) gives minimum bearing friction;

c) gives minimum bearing vibration;

d) gives minimum bearing temperature rise.

8. The film thickness in EHL is

a) directly proportional to the entraining velocity;

b) decreases as the reduced radius is increased;

c) is theoretically zero if the surfaces are travelling at the same speed but in opposite directions;

d) increases as the elastic moduli of the contacting surfaces increases.

9. The major mechanism of friction reduction in boundary lubrication involves,

a) increasing the hardness of the surface oxide;

b) weakening of the surface material;

c) increasing the yield strength of the surface material;

d) suppressing adhesion between contact interfaces.

10. An elastomer seal slides against the steel shaft of a hydraulic linear actuator. What coating would be preferred to reduce both friction and wear in an environment contaminated by hard sand and dust particles?

a) Titanium nitride on the seal;

b) Titanium nitride on the shaft;

c) Teflon on the seal;

d) Teflon on the shaft.