1. Which test is used to measure the resistance to flow of the lubricating oil?
a) Pour point test
b) Gravity test
c) Colour test
d) Velocity test
Discussion
Explanation: The viscosity of a fluid is the measure of its resistance to flow. The oil should be viscous enough to maintain a fluid film between the bearing surfaces. In order to measure viscosity of lubricating oil, an instrument called Saybolt viscosimeter is used.
2. What is Poiseuille’s law?
a) η=\(\frac{πpr^4 t}{8Vl} \)
b) η=\(\frac{πpr^4 t}{16Vl} \)
c) η=\(\frac{πpr^4 t}{32Vl} \)
d) η=\(\frac{3πpr^4 t}{8Vl} \)
Discussion
Explanation: Poiseuille’s law is a physical law that gives the pressure drop in an incompressible and Newtonian fluid in laminar flow flowing through a long cylindrical pipe of constant cross section.
Formula for Poiseuille’s law is: η=\(\frac{πpr^4 t}{8Vl} \)
3. What is viscosity index (V.I.)?
a) V.I.=\(\frac{L-U}{L-H}\)*100
b) V.I.=(L-U)+(L+H)
c) V.I.=(L-U)*(L+H)
d) V.I.=\(\frac{L-H}{L-U}\)*100
Discussion
Explanation: Viscosity index is an arbitrary measure for the change of viscosity with variations in temperature. The lower the VI, the greater the change of viscosity of the oil with temperature and vice versa. It is used to characterize viscosity changes with relation to temperature in lubricating oil.
4. Which of the following is not a system of lubrication used on stationary engines, tractor engines and automobiles?
a) Splash system
b) Thermosiphon method
c) Forced feed system
d) Combination of splash and forced feed
Discussion
Explanation: Thermosiphon method is a method of water cooling. It consists of radiator, water jacket, fan, temperature gauge and hose connections. The system is based on the principle that heated water which surrounds the cylinder becomes lighter in weight and it rises upward in liquid column.
5. In which type of filter does the entire quantity of oil is forced to circulate through it before it enters the engine?
a) Oil pressure gauge
b) By pass filter
c) Full flow filter
d) Crankcase breather
Discussion
Explanation: In full flow filter the entire quantity of oil is forced to circulate through it before it enters the engine. A spring-loaded valve is usually fitted in the filter as a protection device against oil starvation in case of filter getting clogged.
6. Which of the following is a semi fluid lubricant, used for slow moving parts?
a) Grease
b) Crankcase breather
c) Relief valve
d) Oil pressure gauge
Discussion
Explanation: Grease is a semi fluid lubricant, used for slow moving parts. It is useful for those parts, which are connected and are not easily accessible, such as universal joints, water pumps, wheel and axle bearings. Grease consists of a mixture of mineral oil and metallic soap along with a few other chemicals.
7. Which of the following is lubrication theory?
a) Fluid film theory
b) Boundary layer theory
c) Fluid film & Boundary layer theory
d) Thermosiphon theory
Discussion
Explanation: According to fluid film theory, the lubricant is supposed to act like mass of globules, rolling in between two surfaces. It produces a rolling effect whereas according to boundary layer theory, the lubricant is soaked in rubbing surfaces and forms oily surface over it.
8. Which test is used to indicate the fire hazards of petroleum products?
a) Colour test
b) Carbon residue test
c) Pour point test
d) Flash fire test
Discussion
Explanation: When an oil is heated to its approximate boiling point, vapour is given off fast enough to burn when contacted with a spark of a flame. The temperature at which vapour flashes momentarily is called Flash point.
9. When did the term ‘tractor’ appeared first on record?
a) 1973
b) 1996
c) 1890
d) 1880
Discussion
Explanation: George H. Harris of Chicago invented a tractor or traction engine in 1890. The tractor word appeared first on record in patent issued on a traction engine.
10. A towed wheel with rolling radius of 0.35 m and normal load of 500 N requires a horizontal force of 50 N to move it forward. The vertical soil reaction against the wheel can be considered to act ahead to vertical line passing through the wheel at a distance of ________
a) 3.18 * 10-1 m
b) 3.5 * 10-1 m
c) 3.18 * 10-2 m
d) 3.5 * 10-2 m
Discussion
Explanation: (T.F.) * r = R. e
e = \(\frac{[(T.F.).r]}{R}=\frac{50*0.35}{500} \)
= 3.5 * 10-2 m.