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Mechanical-EngineeringFull description
Report for a training conducted in Automobile maintenance.Full description
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Mechanical engineering is the discipline that applies engineering physics, engineering mathematics, and materials science principles to design, analyze, manufacture, and maintain mechanical systems. It is one of the oldest and broadest of the enginee
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1) Which type of friction is there between the rubber tire and road? a) b) c) d)
Static Dynamic Rolling friction Cannot be determined
2) What is minimum age for getting driving license l icense in Nepal ? a) b) c) d)
16 for two wheelers, 18 for light four wheelers, 21 for heavy four wheelers 16 for two wheelers, 18 for light four wheelers, 22 for heavy four wheelers 18 for two wheelers, 10 for light four wheelers, 22 for heavy four wheelers 16 for two wheelers, 20 for light four wheelers, 24 for heavy four wheelers
3) In a four stroke cycle, the minimum temperature inside the engine cylinder occurs at a) Beginning of suction stroke b) End of suction stroke c) Beginning of exhaust stroke d) End of exhaust stroke
4) The spark ignition engines are governed by a) b) c) d)
Hit and miss governing Qualitative governing Quantitative governing Combination of (b) and (c)
5) The probability of knocking in diesel engines is increased by a) b) c) d)
High self-ignition temperature Low volatility Higher viscosity All of these
6) The quality of diesel oil is expressed by a) b) c) d)
Octane number Cetane number Calorific value Mach number
7) The octane number of petrol, generally available, is a) b) c) d)
20 to 40 40 to 60 60 to 80 80 to 100
8) Alpha-methyl-naphthalene Alpha-methyl-naphthalene has the cetane number of a) b) c) d)
0 50 100 120
9) The mechanical efficiency of engine is given by a) =
b) =
. . . .
c)
=
.×. 100
d) None of these
10) Morse test is conducted for a) b) c) d)
Petrol engines Diesel engines Multi cylinder engines All of these
11) The basic part of the engine, to which the other engine parts are attached or assembled is the a) b) c) d)
Cylinder head Cylinder block Crankshaft Oil pan
12) The materials used for cylinder block are a) b) c) d)
Cast iron and steel Cast iron and aluminum alloy Steel and aluminum alloy Brass and steel
13) The motion of cam is transferred to valves through a) b) c) d)
Pistons Rocker arms Camshaft pulley Valve stems
14) The specific gravity of petrol is about a) b) c) d)
0.75 0.85 0.95 1.25
15) The firing order for in line four cylinder engine is a) b) c) d)
1-2-3-4 1-3-4-2 1-4-3-2 1-3-2-4
16) The self-ignition temperature of diesel as compared to petrol is a) b) c) d)
Higher Lower Same Depends on fuel quality
17) Tachometer in vehicle measures a) b) c) d)
Speed Distance Engine rpm Fuel consumption
18) The full form of ABS is a) b) c) d)
Automatic braking system Antilock braking system Antiskid braking system None of the above
19) Mixing of fuel and air in case of diesel engine occurs in a) b) c) d)
Combustion chamber Carburetor Injector Fuel pump
20) Diesel engine as compared to petrol engine requires a) b) c) d)
Bigger flywheel Smaller flywheel Same size flywheel No flywheel
21) For earth moving machines, widely used engines are a) b) c) d)
Petrol engine Diesel engine Steam engine Gas engine
22) Which of the following is not true for internal combustion engine as compare to external combustion engine? a) b) c) d)
It has lower ratio of weight to output They are self-starting Higher overall efficiency Mechanical simplicity
23) The ascending order of strokes in four stroke engine is a) b) c) d)
24) The compression ratio in a Compression Ignition (CI) engine is generally in between a) b) c) d)
8 to 13 14 to 23 20 to 28 25 to 32
25) The compression ratio in a Spark Ignition(SI) engine is generally in between a) b) c) d)
6 to 10 14 to 23 20 to 28 25 to 32
26) In a petrol engine, the mixture has the lowest pressure at the a) Beginning of suction stroke b) End of suction stroke c) End of compression stroke d) None of the above 27) If petrol is used in diesel engine, t hen a) Low power will be produced b) Efficiency will be low c) Higher knocking will occur d) Black smoke will be produced 28) The color of exhaust from diesel engine is generally a) White b) Bluish c) Black d) Violet 29) The pressures at the end of compression stroke in petrol and diesel engine are a) 10 and 20 bar b) 10 and 25 bar c) 15 and 35 bar d) 10 and 35 bar 30) The spark ignition engines are governed by a) Hit and miss governing b) Qualitative governing c) Quantitative governing d) Combination of b and c 31) The spark plug gap is kept between a) 0.3 to 0.7 mm b) 0.2 to 0.8 mm c) 0.4 to 0.9 mm d) 0.6 to 1.0 mm 32) A petrol engine has compression ratio from a) 6 to 10 b) 10 to 15 c) 15 to 25 d) 25 to 40 33) A diesel engine has compression ratio from a) 6 to 10 b) 10 to 15 c) 15 to 25 d) 25 to 40 34) The combustion in compression ignition engines is a) Homogenous b) Heterogeneous c) Both (a) and (b)
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d) None of these 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 10000 volts d) 10000 to 12000 volts Supercharging is the process of supplying the intake air to the engine cylinder at a density ………… the density of surrounding atmosphere. a) Equal to b) Less than c) Greater than d) Either of them Supercharging ………………. the power developed by engine. a) Has no effect b) Increases c) Decreases d) Depends on the condition The compression ignition engines are governed by a) Hit and miss governing b) Quality governing c) Quantity governing d) Combination of (b) and (c) The air fuel ratio in petrol engine is governed by a) Carburetor b) Injector c) Governor d) None of these Which of the following is the part of air cooling system? a) Fan b) Pump c) Radiator d) Fins The correct mixture strength(by weight) for petrol is a) 14.6:1 b) 18.5:1 c) 20.4:1 d) 18:1 High speed compression ignition engines operate on a) Otto cycle b) Diesel cycle c) Dual combustion cycle d) All of these Injection pressure in diesel engine is about a) 10 bar
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b) 100 bar c) 150 bar d) 500 bar The loud pulsating noise heard within the cylinder of an internal combustion engine is known as a) Detonation b) Turbulence c) Pre-ignition d) Supercharging Detonation is also called as a) Knocking b) Pinking c) Resonance d) Both (a) and (b) The knocking in diesel engines may be prevented by a) Reducing delay period b) Raising compression pressures c) Increasing inlet air pressure d) All of the above In diesel engines, the duration between t he time of injection and ignition, is known as a) Pre- ignition b) Delay period c) Ignition period d) Burning period The higher combustion chamber wall temperature in com pression ignition engine will …………. knocking tendency a) Increase b) Reduce c) Not effect d) Depends on air pressure The knocking tendency in spark ignition engines may be prevented by a) Controlling air fuel mixture b) Controlling ignition timing c) Controlling the exhaust temperature d) Reducing the compression ratio Knocking in diesel engines may be prevented by a) Reducing the delay period b) Raising the compression ratio c) Increasing the inlet pressure of air d) All of these The ignition quality of petrol is expressed by a) Cetane number b) Octane number c) Calorific value d) None of these
52) The ignition quality of diesel is expressed by e) Cetane number f) Octane number g) Calorific value h) None of these 53) The cetane number of diesel, gener ally available, is a) 20 to 25 b) 25 to 30 c) 30 to 40 d) 40 to 55 54) Iso- octane ( C8H18) has the octane number of a) 0 b) 1 c) 50 d) 100 55) Alpha- methyl- naphthalene(C11H10) has the cetane number of a) 0 b) 1 c) 50 d) 100 56) N- heptane ( C7H16) has the octane number of a) 0 b) 1 c) 50 d) 100 57) The cetane ( C16H34) which is a straight chain paraffin has the cetane number of a) 0 b) 1 c) 50 d) 100 58) A fuel of an octane number rating 75 matches in knocking intensity as a mixture of a) 75% iso- octane and 25% normal heptane b) 25% iso- octane and 75% normal heptane c) 75% diesel and 25% petrol d) 75% petrol and 25% diesel 59) Which of the following fuel has little tendency towards detonation a) Benzene b) Iso- octane c) Normal heptane d) Alcohol 60) In petrol engines, the delay perio d is of order of a) 0.001 sec b) 0.002 sec c) 0.003 sec
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d) 0.004 sec The operation of forcing additional air into the combustion chamber during suction stroke is known as a) Supercharging b) Carburation c) Turbulence d) Delay period The power actually developed by the engine cylinder of an IC engine is known as a) Theoretical power b) Actual power c) Indicated power d) None of these The brake power is available a) In the engine cylinder b) At the crankshaft c) At crank pin d) None of these The friction power is given by a) F.P. = B.P. – I.P b) F.P. = I.P. – B.P. c) F.P. = B.P./I.P. d) F.P. = I.P./B.P. The thermal efficiency of petrol and gas engine is about a) 14% b) 30% c) 50% d) 70% The thermal efficiency of diesel engine is about a) 14% b) 30% c) 50% d) 70% The primary fuel used in nuclear power plant is a) U235 b) U238 c) Pu239 d) Pu233 Uranium has isotopes a) U234 b) U235 c) U238 d) All of these The effective inhibitor of pre ignition is a) Alcohol
b) Water c) Lead d) None of these 70) The ratio of work obtained at the crankshaft in the given time to the energy supplied during the same time is known as a) mechanical efficiency b) overall efficiency c) indicated thermal efficiency d) volumetric efficiency
