Wednesday, 1 May 2019

RRB EXAM USED MECHANIC MOTOR VEHICLE (THEORY) QUESTIONS SEMESTER – II

MECHANIC MOTOR VEHICLE

(THEORY)

SEMESTER – II

JULY 2018

Which of the following is not true for internal combustion
engine as compare to external combustion engine?
a. It has lower ratio of weight to output
b. They are self-starting
c. Higher overall efficiency
d. Mechanical simplicity
Answer : b. They are self-starting

Which of the following is not an internal Combustion (IC) engine?
a. Gas engine
b. Wankel engine
c. Jet engine
d. Sterling engine
Answer : d. Sterling engine

In two stroke engine there is one power stroke in_of crankshaft rotation.
a.  90°
b. 180°
c. 270°
d. 360°
Answer : d. 360°

In four stroke engine which of the following is also known as power stroke-
a. Suction stroke
b. Compression stroke
c. Expansion stroke
d. Exhaust stroke
Answer : c. Expansion stroke

Thermal stress in cylinder liners can be reduced by……..
a. Increasing the wall thickness of cylinder liner
b. Increasing velocity of flowing water through jacket
c. Both(a)&(b)
d. None of the above
Answer : b. Increasing velocity of flowing water through jacket

Exhaust valve diameter is_intake valve.
a. Greater than
b. Same as
c. Smaller to
d. Double to
Answer : c. Smaller to

Piston slap results from excessive clearance berween ….
a. Piston and cylinder wall
b. Piston and piston pin
c. Piston and piston
d. Piston rings
Answer : a. Piston and cylinder wall


The connecting rod attaches the piston to. The ……
a. Cylinder head
b. Crankshaft
c. Camshaft
d. Driveshaft
Answer : b. Crankshaft

Piston rings are made of-
a. Cast iron
b. Brass
c. Copper
d. Both (a) & (b)
Answer : a. Cast iron

On which two strokes are both valves closed?
a. Intake and exhaust
b. Intake and compression
c.   Compression and power
d.   Power and exhaust
Answer : c.   Compression and power

What is the material of the connecting rod-
a. Mild steel .
b. Forged steel
c. Tool steel
d. Cast iron
Answer : b. Forged steel

Fly wheel is installed on -
a. Crank shaft
b. Cam shaft
c. Both (a) & (b)
d. None of these
Answer : a. Crank shaft

Hydrocarbons are decomposed into smaller hydrocarbons by ….
a. Reforming
b. Refining
c. Cracking
d. Polymerization
Answer : c. Cracking

Which of the following isn't a cylinder block part?
a. Cylinder in which piston slides up and down
b. Openings for valves
c. Passages for flow of cooling water
d. Carburettor
Answer : d. Carburettor
A machine member used to connect engine shaft to gear box is called
a. Differential
b. Clutch
c. Flywheel
d. Propeller shaft
Answer : b. Clutch

A gas turbine works on which cycle?
a. Carnot.     .       ..
b. Brayton
c. Dual cycle
d. Rankine cycle
Answer : b. Brayton

Which among these is the main component of a gas turbine plant?
a. Condenser 
b. Compressor
c. Boiler
d. Both (b) & (c)
Answer : b. Compressor

The gasoline engine works on which cycle?
a. Otto cycle
b. Diesel cycle
c. Brayton cycle
d. None of these
Answer : a. Otto cycle

The turbocharged diesel'ehgine requires ……….. cooling air
than naturally aspired diesel engines.
a. Less
b. More
c. Equal
d. None of these
Answer : b. More

Which of the following is true in radiator …………
a. Relatively small amount of water are brought into
contact with large surface areas of metal
b. Relatively large amount of water are brought into
contact with small surface areas ot metal
c. Equal amount of water are brought into contact
with equal surface areas ot metal
d. Anv of  the above
Answer : a
A typical cooling system circuit has the thermostat between …..
a. Engine outlet and radiator
b. Radiator outlet and engine inlet
c. Both (a) & (b)
d. None of these
Answer : a. Engine outlet and radiator

Lubricating oil ………..
a. Minimizes wear in moving parts 
b. Helps in keeping the parts cool .     
c. Washes away and carries away
d. All of these
Answer : d. All of these

Viscosity index (VI) is a measure for the change of  
viscosity with change in ………
a. Temperature
b. Pressure
c. Volume
d. All of these
Answer : a. Temperature

The following part is not lubricated by Pressure feed system …..
a. Timing gears
b. Valve rods and Push rods
c. Rocker arms
d. Main bearings of crankshaft
Answer : b. Valve rods and Push rods

Supercharging -
a. Increases intake pressure
b. Increases intake temperature
c. Increases flame speed
d. All of these
Answer : d. All of these
Turbochargers are generally-
a. Centrifugal compressors
c. Vane blowers
b. Reciprocating compressors       
d. Roots blower
Answer : a. Centrifugal compressors

In which of the following compressors,
a slip coupling is used between the engine
and compressor for the variable speed
operations of the engines?
a. Piston cylinder type
b  Root blower
c. Vane type blower
d. Centrifugal compressor
d. Centrifugal compressor

If  the temperature of intake air in I.C. engine is
lowered, then its efficiency will ………..
a. Increase
b. Decrease
c  Remain same
d.   No effect
Answer : a. Increase

Air fuel ratio for idling speed of a petrol engine is approximately …
a. 1:1
b. 5:1
c. 10:1
d. 15:1
Answer : c. 10:1

A muffler between the exhaust manifold and
 the end of the exhaust pipe causes …………..
a. A decrease in exhaust gas pressure
b. An increase in exhaust gas pressure
c. No change in exhaust gas pressure
d. Either (a) or (b) .
Answer : b. An increase in exhaust gas pressure

The air fuel ratio of the petrol engine is controlled by ……….
a. Fuel pump
b. Governor 
c. Injector
d. Carburettor
Answer : d. Carburettor

In a diesei engine, the fuel is ignited by-
a. Spark
b. Injected fuel
c. Heat resulting from compressing air that is supplied for combustion
d. Ignition
Answer : c
ECU enabled electronic injection system is used for -
a. Calculating the appropriate injection timing
b. Meeting only certain operating conditions
c. Closing the injection valve only
d. None of the above
Answer : . None of the above
Scavenging air in diesel engine means -
a. Air used for combustion sent under pressure
b. Forced air for cooling cylinder
c. Burnt air containing products of combustion
d. Air used for forcing burnt gases out of engines
cylinder during the exhaust period
Answer : d
Fuel is injected in a four-stroke CI engine-
a. At the end of suction stroke
b. At the end of expansion stroke
c. At the end of compression stroke
d. At the end of exhaust stroke
Answer : c. At the end of compression stroke

……….. of fuel is independent of cranking speed and
therefore starting will be easier,
a. Ignition
b. Atomization
c. Condensation
d.  None of these
Answer : b. Atomization
When the engine is cold, the  ………….. plate
will be in closed position.
a. Nozzle
b. Throttle
c. Air
d. None of these
Answer : b. Throttle

Fugitive emissions consist of-
a. Street dust
b. Dust from construction activities
c. Dust from farm cultivation
d. All of these
Answer : d. All of these

The function of automobile catalytic converter is to
control emissions of-
a. Carbon dioxide and hydrogen
b. Carbon monoxide and hydrogen
c. Carbon monoxide and carbon dioxide
d. Carbon monoxide and nitrogen dioxide
Answer : d . Carbon monoxide and nitrogen dioxide
Gaseous pollutants include-
a. Biological decay
b. Forest fires
c. Volcanic eruptions
d. All of these
Answer : d. All of these

An alternator is also called ……….
a. Synchronous generator
b. Turbo generator
c. Asynchronous generator
d. Generator
Answer : a. Synchronous generator
To get a maximum output current, IC regulation
are provided with
a. Radiation source
b. Heat sink
c. peak detector                                                                                                                                                                                     d. None of these                                                                                                                                                                     Answer : b. Heat sink

3 - point starter is used to start the ……..  
a. Series motor
b. Shunt motor
c. Compound motor                                                                                                                                                                               d. only (b)and (c)                                                                                                                                                                        Answer : d. only (b)and (c)
The full form of MPF1 is ……….
a. Multi Point Fuel Injection
b. Multi Piston Fuel Injection
c. Main Point Fuel Injection
d. Multi Point Fuel Ignition
Answer : a. Multi Point Fuel Injection
EGR stands for -
a. Exhaust Gas Recirculation
b. Engine Gas Recirculation
c. Engine Gas Recycling
d. Exhaust Gas Re-injection
Answer : a. Exhaust Gas Recirculation

To prevent overload and overheating of wires-
a. Fuses are used only
b. Circuit breakers are used only
c. Fuses and circuit breakers are used
d. Fuses and resistor are used
Answer : c. Fuses and circuit breakers are used

The effects of  knocking are ……..
a. Noise and roughness
b. Mechanical damage .  
c. Carbon deposits
d   Allot these
Answer: a. Noise and  roughness
A hydraulic coupling belongs to the category of ………
a. Power absorbing machines
b. Energy transfer machines
c. Power developing machines
d. Energy generating machines
Answer: d. Energy generating machines

In water cooling, the water in the jackets obtains heat from the.
Cylinders due to-
a. Conduction
b. Convection
c. Radiation                                                                                                                                                                                d. All of these
Answer: a. Conduction
Which of the following is the most abundant hydrocarbon
which is emitted into the atmosphere by biological activity?
a. Ethane
b. Methane
c. Poly Aromatic hydrocarbons
d. Pentane
Answer: b. Methane



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