Engineering Questions with Answers - Multiple Choice Questions
Applied Chemistry MCQ – Selection of Lubricants
A high temperature lubricants used may undergo ________
Explanation: A high temperature lubricants used may undergo volatilization. The vulcanization is the process of rubber in presence of sulphur.
For heavy cutting, the effective lubricants are _________
a) coconut oils
b) cutting oils
Explanation: The cutting oils are most suitable oils for heavy cutting. The lubricants contain the additives like fatty oils and sulphurized fatty oils and chlorinated compounds.
The reduction in friction is only when _________ of the oil film is __________ than that of the metal.
a) shear strength, more
b) shear strain, less
c) shear strain, more
d) shear strength, less
Explanation: The friction in friction is only when shear strength of the oil film must be less than the metal. This will reduce the electricity consumption.
The friction is needed to be reduced because _________
a) will increase the load
b) will increase the consumption electricity
c) it will be reducing the excess heat generation
d) will increase the excess the heat generation
Explanation: The friction is needed to be reduced because it will be reducing the excess heat generation which will improve the machine life period.
Oil emulsions are the most effective lubricants in _________
a) heavy cuttings
b) light cutting
Explanation: Oil emulsions are the most effective lubricants in light cuttings. The emulsions have less lubricating effects than that of cutting oils but cutting oils are good as cooling media.
The lubricant in internal combustion is exposed to _________
a) high pressure
b) low pressure
c) low temperature
d) high temperature
Explanation: The lubricant in internal combustion is exposed to high temperatures. So, the lubricant must have the high thermal stability.
The lubricants that are suitable for internal combustion engines must have ______ viscosity index.
Explanation: The lubricant that is used in internal combustion engines must have the high viscosity index because it is exposed very high temperatures that are produced by the engines.
In gears, the lubricants are exposed to _______
a) high temperature
b) high pressure
c) low temperature
d) low pressure
Explanation: In gears, there will be high pressure so, the lubricants are exposed to high pressure and in the high temperatures will be in internal combustion engines.
The lubricants for gears must possess _________
a) less oiliness
b) effected by centrifugal force
c) resistance to oxygen
d) low load carrying capacity
Explanation: For gears, the lubricants must have the resistance to oxygen. The oxygen reacting with metal will form rust and makes the machine damages. so; the lubricants must have resistance towards the oxygen.
For, delicate instruments the suitable lubricants are _________
a) light cutting oil
b) sunflower oil
c) heavy cutting oil
d) thin vegetable oil
Explanation: For delicate instruments, suitable lubricants are very soft ones. They may be like thin vegetable oil, palm oil etc.
What are the lubricants used for railway tracks?
c) coconut oil
d) vegetable oil
Explanation: For railway tracks, the lubricants used are solid lubricants as they are exposed to sun light and must bear the other climatic conditions.
What is the best lubricant for tractor roller?
b) heavy oil
d) vegetable oil
Explanation: Generally, grease is used for the tractor rollers as they are high pressure and low speed vehicles. Grease is a cheaper one.
The lubricants for transformers must have quality of good ________
a) dielectric strength
b) less oiliness
c) no resistance to oxygen
d) low load capacity
Explanation: The di electric must be good for the transformers. They are dried, washed and filtered properly and applied with lubricants.
In textile industries _________ are added to the lubricants.
Explanation: Inhibitors are the negative catalysts that are added to the thin oils which are used as lubricants. This is to improve the sped of the machine and smooth running.
The lubricants used in refrigerators will have ________
a) no pour point
b) high viscosity
c) high pour point
d) low cloud point
Explanation: Generally, napthalene and base oils are used as lubricating oils in the refrigerators. They must have the low cloud point, low pour point and low viscosity.