1. The viscosity of the oil changes rapidly with the change in temperature has _______
a) High V.I
b) Low V.I
c) Moderate V.I
d) Zero V.I
Explanation: The viscosity of some lubricating oils changes by the change in the temperature very rapidly. For such oils the V.I will be zero and for the viscosity of the oils which changes slightly with the change in temperature will have V.I high.
2. Addition of linear polymers to the increases the V.I and oils with V.I higher than _______ are prepared.
a) 100
b) 1000
c) 10000
d) 100000
Explanation: Addition of the linear polymers to the increases the V.I and oils V.I higher than 100 are prepared. Generally, the viscosity is the only factor that decides the thickness of the oil or lubricating liquid.
3. If the viscosity must not be ________ to a liquid oil film between two moving liquid.
a) High
b) Low
c) Moderate
d) Zero
Explanation: The viscosity the most important and the only property of the lubricating oils to determine the thickness and velocity of the liquid. If the viscosity of an oil is too low then it is impossible to maintain liquid oil film between two moving or sliding liquids.so, every liquid must have good viscosity value.
4. Excessive friction takes place, when the viscosity is ________
a) Too high
b) Too low
c) Moderate
d) Zero
Explanation: The excessive friction takes place when the viscosity of the lubricating oil is too high. As the viscosity is too high then the layers of the sliding liquids will be moving fast and overlap on one another and causes the excess friction.
5. The viscosity of the lubricating oil must be sufficient to keep it in position.
a) True
b) False
Explanation: The viscosity of the lubricating must not be low. It also should not be too high. If it is too high then the liquid flow more faster and causes high or excessive friction. If it is low then the liquid moves very slowly and have low friction. Sufficient viscosity should be there to keep a liquid in a position.
6. ________ is used in machines operating at high pressure and slow speeds.
a) Kerosene
b) Diesel oil
c) Heavy oil
d) Crude oil
Explanation: Heavy oil is used as a lubricant in the machines that are operated at low speed under high pressure. The heavy oil is used as it has resist the squeezing between the rubbing parts while operating the machine.
7. For machines operating at the high speed and low pressure __________ are used.
a) Heavy oils
b) Light oils
c) Crude oils
d) Diesel oil
Explanation: For machines operating at the high speed and low pressure, the lubricating oil use is light oil. The light oil do not impose as much drag on high speed parts. Therefore, for the minimum friction, the thinner oil stays at position.
8. Redwood viscometer no1 is used to find the viscosity of the _________ liquids.
a) High viscous
b) Low viscous
c) Moderate viscous
d) No viscous
Explanation: The redwood viscometer no1 is used to find out the viscosity of the low viscous liquids. They have an efflux of 2000seconds or less. Redwood viscometer no2 is used to find the viscosity of the high viscous liquids like fuel oils.
9. What is the efflux of the redwood viscometer no2?
a) 2000
b) 20000
c) 100
d) 200
Explanation: The efflux of the redwood viscometer no2 is 200 seconds or less. Its jet for the outflow of the oil is having larger diameter. We can find the relative viscosities of the liquids using the redwood viscometer.
10. Test thermometer is one of the parts of the redwood viscometer.
a) True
b) False
Explanation: The parts of the redwood viscometer are test thermometer, bath thermometer, water inlet, oil stirrer, water bath, heating coil, metal indicator, brass oil cup, water bath stirrer blade, valve rod, water outlet, agate jet, kohlrausch flask and levelling screw.