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Home » Engineering » Mechanical Engineering » Aptitude Test - 8
1.What happens to viscosity in the case of incompressible fluids as temperature is increased?
A. It remains constant
B. It increases
C. It decreases
D. It remains constant
2.If a fluid, which has a constant specific gravity, is taken to a planet where acceleration due to gravity is 3 times compared to its value on earth, what will happen to its kinematic viscosity.
A. It increases
B. It decreases
C. It remains constant
D. It increases
3.In liquids in order to measure the viscosity of fluid experimentally we consider the variation of shear stress with respect to what property?
A. strain
B. shear strain
C. rate of shear strain
D. strain
4.Which of the following is the condition for the boiling of a liquid?
A. Absolute pressure of a liquid must be greater than or equal to it’s vapor pressure
B. Absolute pressure of a liquid must be less than or equal to it’s vapor pressure
C. Absolute pressure of a liquid must be equal to it’s vapor pressure
D. Absolute pressure of a liquid must be greater than or equal to it’s vapor pressure
5.Which of the following machines have the possibility of cavitation?
A. Reaction turbines and centrifugal pumps
B. Reaction turbines and reciprocating pumps
C. Impulse turbines and centrifugal pumps
D. Reaction turbines and centrifugal pumps
6.The three liquids 1, 2, and 3 with vapor pressures V1, V2 and V3 respectively, are kept under same pressure. If V1 > V2 > V3, which liquid will start boiling early?
A. liquid 1
B. liquid 2
C. liquid 3
D. liquid 1
7.Equal amount of a particular liquid is poured into three similar containers, namely 1, 2 and 3, at a temperature of T1, T2 and T3 respectively. If T1 < T2 < T3, the liquid in which container will have the highest vapor pressure?
A. container 1
B. container 2
C. container 3
D. container 1
8.The absolute pressure of a water is 0.5kN above it’s vapor pressure. If it flows with a velocity of 1m/s, what will be the value of Cavitation Number describing the flow induced boiling?
A. 0.25
B. 0.5
C. 1
D. 0.25
9.The reference fuels for knock rating of spark ignition engines would include
A. iso-octane and alpha-methyl naphthalene
B. normal octane and aniline
C. iso-octane and normal hexane
D. iso-octane and alpha-methyl naphthalene
10.In a four stroke cycle, the minimum temperature inside the engine cylinder occurs at the
A. beginning of suction stroke
B. end of suction stroke
C. beginning of exhaust stroke
D. beginning of suction stroke
11.The thermal efficiency of a standard Otto cycle for a compression ratio of 5.5 will be
A. 25%
B. 50%
C. 70%
D. 25%
12.The ratio of the volume of charge admitted at N.T.P. to the swept volume of the piston is called
A. mechanical efficiency
B. overall efficiency
C. volumetric efficiency
D. mechanical efficiency
13.The exhaust valve in a four stroke cycle petrol engine
A. opens at 50° before bottom dead centre and closes at 15° after top dead centre
B. opens at bottom dead centre and closes at top dead centre
C. opens at 50° after bottom dead centre and closes at 15° before top dead centre
D. opens at 50° before bottom dead centre and closes at 15° after top dead centre
14.Nuclear reactors are used
A. to produce heat for thermoelectric power
B. to produce fissionable material
C. to propel ships, submarines, aircrafts
D. to produce heat for thermoelectric power
15.A moderator generally used in nuclear power plants is
A. graphite
B. heavy water
C. concrete
D. graphite
16.The predominent isotope of the naturally occuring element is
A. U235
B. U238
C. Pu233
D. U235
17.In a four stroke cycle petrol engine, the charge is ignited at
A. 30° before top dead centre
B. 30° after top dead centre
C. 30° before bottom dead centre
D. 30° before top dead centre
18.A moderator, in nuclear power plants, is a medium introduced into the fuel mass in order to
A. slow down the speed of fast moving neutrons
B. control the reaction
C. reduce the temperature
D. slow down the speed of fast moving neutrons
19.Where reactor operation is designed with fast neutrons such as in reactors using highly enriched fuel, the moderator used is
A. heavy water
B. graphite
C. carbon dioxide
D. heavy water
20.In a diesel engine, the duration between the time of injection and ignition, is known as
A. pre-ignition period
B. delay period
C. period of ignition
D. pre-ignition period
21.Each fission of U235 produces on the average __________ fast neutrons as a product of reaction.
A. 2.46
B. 24.6
C. 246
D. 2.46
22.Reactors for propulsion applications are designed for
A. any form of uranium
B. natura uranium
C. enriched uranium
D. any form of uranium
23.The primary fuel used in nuclear power plants is
A. U235
B. U238
C. Pu239
D. U235
24.In petrol engine, using a fixed octane rating fuel and fixed compression ratio, supercharging will ____ the knocking tendency.
A. not effect
B. decrease
C. increase
D. not effect
25.The compensating jet in a carburettor supplies almost constant amount of petrol at all speeds because the
A. jet area is automatically varied depending on the suction
B. the flow from the main jet is diverted to the compensating jet with increase in speed
C. the diameter of the jet is constant and the discharge coefficient is invariant
D. jet area is automatically varied depending on the suction
26.The effective inhibitor of pre-ignition is
A. alcohol
B. water
C. lead
D. alcohol
27.The purpose of testing an internal combustion engine is
A. to determine the information, which can not be obtained by calculations
B. to conform the data used in design, the validity of which may be doubtful
C. to satisfy the customer regarding the performance of the engine
D. to determine the information, which can not be obtained by calculations
28.The thermal efficiency of diesel engines is about
A. 15%
B. 30%
C. 50%
D. 15%
29.A diesel engine has
A. one valve
B. two valves
C. three valves
D. one valve
30.The self ignition temperature of petrol is _____ as compared to diesel oil.
A. same
B. lower
C. higher
D. same
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