Engineering Questions with Answers - Multiple Choice Questions
Applied Chemistry MCQ – Classification of Lubricants – 1
How many types of lubricants are there on the basis of the shear strength?
Explanation: There are four types of lubricants according to the classification on the basis of the shear strength. They are solid, liquid, semi-solid and gaseous lubricants. Shear strength is the strength against the structural failure of the component.
In solid lubricants, the _________ will be low.
a) coefficient of friction
b) calorific value
Explanation: 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.
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
Explanation: 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.
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
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).
Powder of a solid lubricant delivered to the __________
a) rubbing area
b) composite material
Explanation: The powder of the solid lubricant is delivered to the rubbing area that means dry lubrication and it has good adhesiveness. Composite coating consists of the particles of a solid lubricant and dispersed throughout matrix.
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
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.
Which of the following is not the inorganic lubricant?
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.
Soft metals possess lubrication due to ___________
a) low plasticity
b) high plasticity
c) no plasticity
d) moderate plasticity
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.
Coating and overlays will be done by using _________
a) inorganic lubricants
b) organic lubricants
c) soft metal
Explanation: Soft metals are used in pure forms to produce alloys. They actually used for coatings. They are used in lead based and tin based engine bearing over lays. They are also used in the matrix composite materials.
Soft metal lubricants are produced by using ____________
b) thermal spraying
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.