InterviewSolution
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InterviewSolution
This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
99% of grease is produced from __________(a) petroleum oil(b) olive oil(c) castor oil(d) whale oil |
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Answer» The correct choice is (a) petroleum oil The explanation is: The semi-solid lubricants are generally made by incorporation of the lubricating oil with metallic soap to the liquid lubricants. 99% of the grease is produced from the petroleum oil. Olive oil, castor oil and whale oil are the types of liquid lubricants. |
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| 2. |
A dispersion system consisting of two immiscible liquids is called ________(a) Lubricants(b) Emulsions(c) Semi solids(d) Solids |
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Answer» Right answer is (b) Emulsions The explanation: A dispersion system consisting of two immiscible liquids is called emulsions. A substance is added to the emulsions called emulsifying agents for stabilization. The emulsifying agents show polar or non polar natures accordingly. |
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| 3. |
Insulators making rubbing contact require _______(a) Low conductivity(b) High conductivity(c) Low pressure(d) High pressure |
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Answer» Right option is (a) Low conductivity The best I can explain: Insulators making rubber contact needed low electrical conductivity. In some other applications of the solid lubricants, the high electrical conductivities. Sliding electric contact requires high electrical conductivity. |
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| 4. |
In solid lubricants, the _________ will be low.(a) coefficient of friction(b) calorific value(c) stability(d) cleanliness |
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Answer» The correct choice is (a) coefficient of friction To elaborate: The coefficient of friction will be low for the solid lubricants and it is one of the disadvantages of the solid lubricants. They are stable at high temperatures also. Cleanliness of the solid lubricants is also high. |
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| 5. |
Soft metal lubricants are produced by using ____________(a) purifying(b) thermal spraying(c) distillation(d) electroplating |
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Answer» Correct option is (b) thermal spraying For explanation: Electrotyping and thermal spraying can be used for the production of soft metal lubricants. The distillation and purifying are the processes for cleaning the liquids. |
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| 6. |
The crystal lattice of the inorganic lubricants has a ___________ forming thin parallel planes.(a) octagonal rings(b) hexagonal rings(c) pentagonal rings(d) trigonal rings |
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Answer» Right answer is (b) hexagonal rings Easiest explanation: The crystal lattice structure of the inorganic lubricants has hexagonal rings forming thin parallel planes. Within the plane each atom is strongly bonded with covalent bonds. Each plane is bonded by weak vaanderwal forces. |
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| 7. |
A good liquid lubricant must possess the property of ___________(a) Low viscosity(b) High boiling point(c) High freezing point(d) Low oiliness |
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Answer» The correct option is (b) High boiling point The best I can explain: A good liquid lubricant must possess the properties like adequate viscosity, high boiling point, low freezing point, good oiliness. It also contains stability towards the oxidation and heat. |
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| 8. |
Sodium base greases can be utilized up to the temperature of ____________(a) 175^oC(b) 100^oC(c) 75^oC(d) 80^oC |
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Answer» Correct choice is (a) 175^oC For explanation: Sodium soaps are soluble in water and they are not water resistant. As they are not stabilized with water. They can resist up to a temperature of 175^oC. They can be used at ball and roller bearing at which there will be heat production due to heat. |
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| 9. |
The lubricant should have __________ vapor pressure.(a) High(b) Extreme(c) Moderate(d) Low |
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Answer» Right choice is (d) Low Easy explanation: The ideal lubricant must have low vapour pressure for any application because in most of the applications of the lubricants, the lubricants must have low pressure and high temperature resistant. |
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| 10. |
The more friction of the greases is due to their high __________(a) velocity(b) viscosity(c) temperature coefficient(d) buoyancy |
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Answer» The correct answer is (b) viscosity To elaborate: The more friction of the greases is due to their viscosity. They are very thick semi solid lubricants. If the speed in high then friction is also high and then the heat produced will be more. As, the greases are very poor coolants they will be overheated. |
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| 11. |
Which of the following is not the inorganic lubricant?(a) WS2(b) TiTe2(c) GaS(d) Pb |
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Answer» The correct choice is (d) Pb Easy explanation: Pb is the soft metal lubricant. Sulphides, selenides and telluride’s of molybdenum, tungsten, niobium, tantalum and titanium are comes under the inorganic lubricants. |
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| 12. |
Which of the following are the disadvantages of solid lubricants?(a) poor heat dissipation(b) more effective even at high pressures(c) high resistance to detoriation(d) permit equipment is heavy |
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Answer» The correct option is (a) poor heat dissipation Best explanation: One of the disadvantages of the solid lubricants is poor heat dissipation. They have more ability to perform well at the high load too(under high pressures). |
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| 13. |
Soaps are prepared by chemical treating of _________ by strong alkaline solutions.(a) Oils and salts(b) Oils and fats(c) Salts and fats(d) Fats and proteins |
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Answer» The correct answer is (b) Oils and fats The explanation is: Soaps are made up of the chemical treatment of the oils and fats by strong alkaline solution. The soap molecule is the long non-polar tail which is hydrophobic end and the other is salt polar end which is the hydrophilic end. |
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| 14. |
What is the range of coefficient of friction for solid lubricants?(a) 0.005-0.01(b) 0.001-0.01(c) 0.0001-0.001(d) 0.0005-0.001 |
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Answer» Right option is (a) 0.005-0.01 For explanation I would say: The range of the coefficient of friction for solid lubricants is very less that of 0.005-0.01. This must be low for effective lubrication because the lubricant is mainly used to control the friction between the machine parts. |
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| 15. |
Soft metals possess lubrication due to ___________(a) low plasticity(b) high plasticity(c) no plasticity(d) moderate plasticity |
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Answer» Correct answer is (b) high plasticity The explanation: The soft metals have the high plasticity as they have low shear strength. Lead, tin, bismuth, indium, cadmium and silver are the some of the examples of soft metal lubricants. |
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| 16. |
One of the advantages of the solid lubricants is ___________(a) unstable in radiation(b) high coefficient of friction than liquid lubricants(c) low coefficient of friction(d) permit equipment is simple |
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Answer» The correct option is (d) permit equipment is simple To explain: The permit equipment is simple so that it can be carried anywhere very easily. Normally, the coefficient of friction of the solid lubricant is low and it is a disadvantage. Another disadvantage is it is unstable in radiation. |
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| 17. |
Castor oil is used for _______(a) Plastic industry(b) For guns(c) For sewing machines(d) Light machinery |
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Answer» Correct option is (a) Plastic industry The best I can explain: The castor oil is mainly used for machinery at high speed and low pressure. It is used at plastic industry and medical purposes. For guns and sewing machine the neats foot oil is used. For light machinery, whale oil is used. |
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| 18. |
High mechanical stability is more for ________(a) sodium base greases(b) lithium soap greases(c) complex greases(d) cup greases |
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Answer» Correct choice is (b) lithium soap greases To explain I would say: About 65% of the market is captured by the lithium greases. They have high mechanical stability. They are also stable for storage. They are expensive and used for specific applications like in air crafts. |
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| 19. |
Calcium complex grease can be made from ___________(a) lime, fatty acid, acetic acid(b) calcium, lime, acetic acid(c) calcium, lime, acetic acid(d) lime, calcium, acetic acid |
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Answer» Correct option is (a) lime, fatty acid, acetic acid Easiest explanation: Calcium complex grease is formed out of the lime, fatty acid and acetic acid. The grease can be formed by using the sodium, aluminium and lithium. That is why these lubricants have high melting points. |
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| 20. |
The emulsifiers in water in oil type emulsions are ________(a) Sodium salts(b) Potassium salts(c) Oxides(d) Alkaline earth soaps |
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Answer» The correct choice is (d) Alkaline earth soaps Easy explanation: The emulsifiers in water in oil type are alkaline earth metals. Sulphides, sodium and potassium salts are used in oil in water type emulsion. To prepare water in oil type emulsions, 1-10% of water and emulsifiers are added to the oil. |
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