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Home » Engineering » Mechanical Engineering » Aptitude Test - 10
1.The maximum propulsive efficiency of a turbo-jet engine is at a speed of
A. 1000 km/h
B. 2000 km/h
C. 2400 km/h
D. 1000 km/h
2.In order to mix air and petrol in the required proportion and to supply it to the engine during suction stroke, then __________ is employed.
A. fuel pump
B. injector
C. carburettor
D. fuel pump
3.The advancing of spark timing in spark ignition engines will __________ knocking tendency.
A. increase
B. reduce
C. not effect
D. increase
4.The knocking in spark ignition engines can be reduced by
A. retarding the spark
B. increasing the engine speed
C. both (a) and (b)
D. retarding the spark
5.The ratio of the brake power to the indicated power is called
A. mechanical efficiency
B. overall efficiency
C. indicated thermal efficiency
D. mechanical efficiency
6.The increase of efficiency of a compression ignition engine, as the load decreases, is due to
A. higher maximum temperature
B. qualitative governing
C. quantitative governing
D. higher maximum temperature
7.The cetane (C16H34) which is a straight chain paraffin is assigned a cetane number of
A. 0
B. 50
C. 100
D. 0
8.Morse test is used to determine the I.P. of a
A. single cylinder petrol engine
B. four stroke engine
C. single cylinder diesel engine
D. single cylinder petrol engine
9.A moderator
A. absorbs neutrons
B. does not absorb neutrons
C. accelerates neutrons
D. absorbs neutrons
10.The thermodynamic cycle on which the petrol engine works, is
A. Otto cycle
B. Joule cycle
C. Rankine cycle
D. Otto cycle
11.The inlet valve of a four stroke cycle internal combustion engine remains open for
A. 130�
B. 180�
C. 230�
D. 130�
12.The correct mixture strength (by weight) for petrol is about
A. 14.6:1
B. 18.5:1
C. 20.4:1
D. 14.6:1
13.The working pressure and temperature inside the cylinder of an internal combustion engine is _____ as compared to a steam engine.
A. low
B. very low
C. high
D. low
14.The scavenging efficiency of a four stroke cycle diesel engine is
A. below 50%
B. between 50 and 85%
C. between 85 and 95%
D. below 50%
15.The voltage required to produce a spark across the gap, between the sparking points is
A. 2000 to 4000 volts
B. 4000 to 6000 volts
C. 6000 to 10 000 volts
D. 2000 to 4000 volts
16.The control rods in the control system of nuclear reactors are used to
A. absorb excess neutrons
B. control fuel consumption
C. control temperature
D. absorb excess neutrons
17.If the speed of the engine is increased, the indicated power will
A. increase
B. decrease
C. remain same
D. increase
18.The specific fuel consumption per B.P. hour for a petrol engine is about
A. 0.2 kg
B. 0.25 kg
C. 0.3 kg
D. 0.2 kg
19.The material most commonly used for sheilding is
A. carbon
B. lead
C. concrete
D. carbon
20.In order to eliminate knocking in compression ignition engines, there should be
A. short delay period
B. late auto-ignition
C. low compression ratio
D. short delay period
21.Reflector in nuclear power plants _____ neutron leakage.
A. increases
B. decreases
C. have no effect on
D. increases
22.Number of working strokes per min. for a two stroke cycle engine are __________ the speed of the engine in r.p.m.
A. equal to
B. one-half
C. twice
D. equal to
23.The injector nozzle of a compression ignition engine is required to inject fuel at a sufficiently high pressure in order to
A. inject fuel in a chamber of high pressure at the end of compression stroke
B. inject fuel at a high velocity to facilitate atomisation
C. ensure that penetration is not high
D. inject fuel in a chamber of high pressure at the end of compression stroke
24.A fuel of cetane number 40 has the same ignition quality as a mixture of
A. 40% cetane and 60% alpha methyl napthalene
B. 40% alpha methyl napthalene and 60% cetane
C. 40% petrol and 60% diesel
D. 40% cetane and 60% alpha methyl napthalene
25.The two reference fuels used for cetane rating are
A. cetane and iso-octane
B. cetane and alpha-methyl naphthalene
C. cetane and normal heptane
D. cetane and iso-octane
26.In petrol engines, the delay period is of the order of
A. 0.001 second
B. 0.002 second
C. 0.003 second
D. 0.001 second
27.In a four stroke cycle petrol engine, the pressure inside the engine cylinder during the suction stroke is _____ the atmospheric pressure.
A. equal to
B. below
C. above
D. equal to
28.A diesel engine is ______ as compared to petrol engine, both running at rated load.
A. equally efficient
B. less efficient
C. more efficient
D. equally efficient
29.Which one of the following event would reduce volumetric efficiency of a vertical compression ignition engine ?
A. inlet valve closing after bottom dead centre
B. inlet valve closing before bottom dead centre
C. inlet valve opening before top dead centre
D. inlet valve closing after bottom dead centre
30.The pressure at the end of compression, in petrol engines, is approximately
A. 10 bar
B. 20 bar
C. 25 bar
D. 10 bar
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