MECHANIC MOTOR VEHICLE
THEORY
SEMESTER – IV JULY 2018
a. Homogeneous
b. Heterogeneous
c. Laminar
d. None of these
Answer: a. Homogeneous
The degree of turbulence increases…….…with the piston.speed.
a. Indirectly
b. Directly
c- Linearly
d None of these
Answer: b. Directly
Which one of the following is a CFC refrigerant?
a. R 744
b. R290
c. R 502
d. R718
Answer: c. R 502
Which motion of follower is best for high spee.d cams?
a. SHM follower motion
b. uniform acceleration and retardatior of foll0wer motion
c. Cycloidal motion follower
d. All of.these Answer: c. Cycloidal motion follower
The purpose of a choke on a carburetor is
a. To provide more air for the engine.
b. To increase the life of the engine
c. To make it run at higher rpm’s
d. To make it easier to crank a cold engine
Answer: d. To make it easier to crank a cold engine
In an electronic fuel injection, the servicing is
a. Difficult
b EaSy
c. Very Easy d. None of these Answer: a. Difficult
EF1 system can achieve
a. Proper injection timing
b. Proper injection quantity
c. Proper injection pressure d. All of these Answer: d. All of these
Petrol or Gasoline is obtained from crude petroleum by means of
a. Distillation
b. Cracking
c. Both (a) & (b) d. None of these Answer: c. Both (a) & (b)
Gasoline engines are ………….. than diesel engines. a. Heavier b. Lighter c. Unpredictable d. None of these Answer : b. Lighter
The function of a float chamber in a carburetor is to supply the fuel to the nozzle at a
a. Constant volume head
b. Constant pressure head
c. Variable pressure head d. None of these Answer : . Constant pressure head
The main metering system of the carburetor consists of
a. The fuel metering orifice through which fuel is drawn from the float chamber
b. The main discharge
c. The passage leading to the idling system
d. All of these
Answer : d. All of these
The functions of the main metering system are
a. To proportion the fuel-air mixture
b. To decrease the pressure at the discharge nozzle exit
c. To limit the air flow at full throttle
d. All of these
Answer : d. All of these
In an electronic fuel injection, the maintenance cost is
a. Low
b. High
c. Normal d. None of these Answer : b. High
The main metering system of the carburetor controls the fuel feed for
a. Cruising
b. Full throttle operations
c. Both(a)&(b) d. None of these Answer : c. Both(a)&(b)
In electronic fuel injection, there is improvement in the_efficiency due to
comparatively less resistance in the intake manifolds which will cause less pressure losses.
a. Mechanical
b. Volumetric
C. Overall
d. None of these.
Answer : b. Volumetric
Types of Multi-Point Fuel Injection system are
a. Port injection
b. Throttle body injection
c. Both(a)&(b)
d. None of these
Answer :c. Both(a)&(b)
In MPFI-Electronic Control System, the …………….. sensor sends information about the engine speed.
a. Speed
b. Ignition
c. Air-flow
d. Air-mass
Answer : b. Ignition
The following is not an injector fault
a. Nozzle wetness
b. Blue nozzle body
c. Excessive leak off d. Blowholes Answer : d. Blowholes
Commonly used refrigerant in commercial ice plant is
A C02
b. Freon 12
c. Ammonia d. Air
Standardization of potentiometer is used for
a. Accuracy
b. Accuracy in measurement
c. Use of low voltage sources d. None of these Answer : c. Use of low voltage sources
The main aims of an engine management system is to achieve
a. High reliability and durability with lowest possible initial cost
b. High power output and torque
c. Low levels of gaseous and particulate emissions
d. All of these
Answer : d. All of these
A circuit breaker is
a. Power factor correcting device
b. A device to neutralize the effect of transients
c. A waveform correcting device d. A current interrupting device. Answer : d. A current interrupting device.
The following is (are) the part(s) of Electronic Control Unit (ECU)
a. Injector control
b. Spark advance control
c. Idling control d. All of these Answer : d. All of these
ECU is an electronic injection system used for
a. Calculating the appropriate injection timing
b. Meeting only certain operating conditions
c. Closing the injection valve only
d. None of these
Answer : a. Calculating the appropriate injection timing
Sensitivity of a sensor can be depicted by
a. Niquist plot
b. Pole- zero plot
c. Bode plot
d. None of these
Answer : c. Bode plot
Change in output of sensor with change in input is
a. Threashold
b. Slew rate
c. Sensitivity d. None of these Answer : c. Sensitivity
According to Faraday's law, EMF stands for
a. Electromagnetic field c. Electromagnetic friction
b. Electromagnetic force d. Electromotive force
c. Electromagnetic friction d. Electromotive force Answer : d. Electromotive force
For time varying currents, the field or waves will be
a. Electrostatic
b. Magneto static
c. Electromagnetic d. Electrical Answer :
The following affect the voltage required to jump over the gap of spark plug
a. Shape of electrode forming gap
b. The conductivity of gases in the gap
c. Fuel-air mixture ratio existing in the gap
d. All of these
Answer : d. All of these
Following is (are) true for Hall Effect sensors.
a. They can operate as switches of high frequency
b. They cost less than electromechanical switches
c. They are free from contact bounce problem
d. All of these
Answer : d. All of these
During the charging of a lead-acid cell
a. Its voltage increases
b. It gives out energy
c. Its cathode becomes dark chocolate brown in colour
d. Specific gravity of H₂S0₄ decreases
Answer : a. Its voltage increases
The output voltage of a charger is
a. Less than the battery voltage
b. Higher than the battery voltage
c. The same as the battery voltage
d. None of these Answer : b. Higher than the battery voltage
The function of duct in air conditioning unit is:
a. Air cooling
b. Air cleaning
c. Air drying d. distribution Answer : d. distribution
When speed of an alternator is changed from 3600 r.p.m. to 1800 r.p.m., the generated e.m.f./phases will become
a. One-half
b. Twice
c. Four times d. None of these Answer : a. One-half
Alternating current produced by alternator (AC generator) is converted to DC by
a. Stator
b. Brushes
c. Rectifier d. Regulator Answer : c. Rectifier
Which starter does not provide high speed protection to the D.C. shunt motor?
a. Three point starter
b. Four point starter
c. Two point starter d. None of these Answer :
For the protection of D.C. series motor, which starter is commonly used?
a. Two point starter
b. Three point starter
c. Four point starter d. None of these Answer :
Radio interference from a fluorescent lamp can be reduced by
a. Putting two lamps in parallel
b. Eliminating choke
c. Putting a capacitor across the lamp d. None of these Answer : c. Putting a capacitor across the lamp
Which of the following is difficult to adopt for dimming?
a. GLS lamps
b. Cold cathode lamps
c. Fluorescent lamps d. All of these Answer : c. Fluorescent lamps
The mirror used for the head light of a car is
a. Spherical concave
b Plane
c. Cylindrical
d. Parabolic Concave Answer : d. Parabolic Concave
Nitrogen is added with the argon in an incandescent lamp to
a. Reduce the temperature
b. Reduce the possibility of arcing
c. Increase the brightness d. Increase the efficiency Answer : b. Reduce the possibility of arcing
Latent heat is highest for
a. Refrigerant-22
b. Ammonia
c. Water d. None of these Answer : c. Water
Which is the hottest portion of the poppet valve during operation of S.I engine'
a. Valve face
b. Valve head
c. Valve stem d. Valve neck Answer : b. Valve head
Thermostatic expansion valve is used to maintain
a. Constant degree of superheat
b. Constant degree of sub-cooling
c Constant degree of super heat and sub-cooling d.None of these Answer : a. Constant degree of superheat
The thermostatic valves opens and provides passage for the flow of water towards the radiator at approximately
a. 90° C
b. 150° C
c- 250°C
d. 300°C
Answer : a. 90° C
Inductive proximity sensors can be effective only when the objects are of-materials.
a. Ferromagnetic
b. Diamagnetic
c. Paramagnetic d. All of these Answer : a. Ferromagnetic
Global Positioning System (GPS) is a
a. Satellite Word Station
b. Satellite System
c. Satellite Signal d. Satellite Solution Answer : b. Satellite System
Smallest change which a sensor can detect is
a. Resolution
b. Accuracy
c Precision
d. Scale
Answer : a. Resolution
Choose wrong, size of image formed in a plane mirror
a. Could be taller than mirror
b. Height of image depends on object distance
c. Width of image is same as of object d. Image height depends on object height Answer : a. Could be taller than mirror
Following type of sensors are used to generate information in object grasping and obstacle avoidance.
a. Hall Effect sensor
b. Proximity sensor
c. Light sensor
d. OPtical sensors
Answer : b. Proximity sensor
MECHANIC MOTOR VEHICLE THEORY SEM - IV JAN2018
l. The thermodynarnic cycle on which the petrol engine works, is
a. Joule cycle
b. Otto cycle
c. Rankine cycle
d. Stirling cycle
In four strokes spark ignition engine, at the end of compression stroke, before the spark occurs, what is the pressure developed inside the combustion chamber?
a. 2 to 4 Kg/cmsq
b. 6 to 8 Kg/cmsq
c. 10 to 12 Kg /cmsq
d. 14 to 16 Kg /cmsq
In a four stroke petrol engine, during suction stroke ....
a. Only air is sucked in
b. Only petrol is sucked in
c. Mixture of petrol and air is sucked in
d. None of these
The sequence of 4 stroke cycle operaåon of S.I. engine is —
a. Induction — power — compression — Exhaust
b. Induction Compression — Power— Exhaust
c. Compression — Induction — Power — Exhaust
d. Compression — Power — Induction - Exhaust
In a two s&oke cycle engine, the four process in a cycle namely suction, compression, power (expansion) and exhaust are completed in revolutions of crank shaft.
a. One b. Two c. Three d. Four
In a single cylinder 4 - stroke S.I engine the power stoke starts after of crank
a. 90° b. 180° c, 270° d. 360°
Compression Ratio (CR) of Sel engine is less than C.I. engine because .......
a. It makes the engine lighter
b. Less C.R. gives better performance
c. It is a common practice
d. Higher or equal CR is not possible due to the problem of pre-ignition
T - slot provided in the piston .......
a. To accommodate the expansion of piston when heated up
b. For the passage of lubricafrlg oil
c. For cooling purpose
d. To reduce the weight of piston
The part of crank shaft to which connecting rod is connected is called .........
a. Big end
b. Crank pin
c. Crank web
d. Small end
The pefrol engine gets very rich mixture at the time of -
a. Starting
b. Idling
c. Accelerating
d. Operating at cruising speed
ISO - octane content in the fuel of S.L engine .......
a. Retards auto -ignition
b. Accelerates auto - ignition
c. Does not affect auto -ignition
d. None of these
The volumetric efficiency of a good designed engine may be ......
a. 30 to 40%
b. 40 to 60%
c. 60 to 70%
d. 75 to 90%
The venturi in a carburetor causes ......
a. Increase of air velocity
b. Decrease of air velocity
c. Decrease of fuel flow
d. Decrease of manifold vacuum
The main disadvantage of the mechanical fuel pump is that ......
a. They need to be located near the engine
b. They are prone to vapour lock
c. They operate only after the engine has started
d. All of the above
The throttle valve confrols the supply of ........
a. Air only
b. Fuel only
c. Air fuel mixture
d. None of these
The main advantage of electronic fuel injection (EFI) system is ......
a. High quality fuel distribution
b. Less fuel consumption
c. Rapid response of the engine to throttle control
d. All ofthe above
Which of the following component, in EFI system, decides the amount of fuel to be injected on the basis of signals received from the wide range of sensors?
a. ECU
b. Carburettor
c. Throttle
d. Governor
In EFI system the engine temperature sensor senses the temperature of .......
a. Cooling water at out let
b. Cooling water at inlet
c. Suction air
d. Exhaust gas
In EFI system the inlet Manifold Pressure Sensor senses the —
a. Quantity of Air in the inlet manifold
b. Vacuum in the inlet manifold
c. Quantity of fuel supplied in the inlet manifold
d. Any one of the above
In EFI system the exhaust gas sensor senses the percentage in exhaust gas for calculating air-fuel ratio.
a. NOx b. CO c. 02 d. HC
The rate of flow of electrons in a conductor is known as —
a. Current
b. Voltage
c. Resistance
d. None of these
A is an electrical one way check valve that will allow current to flow in one direction only.
a. Diode
b. Transistor
c. Capacitor
d. Resistor
"Whenever a conductor cuts magnetic flux, an e.m.f. is induced in that conductor." This statement is called as
a. Ohm's law
b. Fleming's rule
c. Faraday' s First law of electromagnetic induction
d. Faraday's second law of elecfromagnetic induction
The Large gap in the spark plug may cause the engine ......
a. Misfiring
b. Over heating
c. Back firing
d. Timing disturbance
The main function of the condenser in an ignition system is .......
a. Minimizing Pitting of the contact breaker points
b. To intensify the spark
c. To absorb the energy stored in the primary winding
d. All ofthe above
In general, the hot plugs haveinsulator nose.
a. Short
b. Thin
c. Long
d. Thick
The vacuum advance mechanism functions at .......
a. Light engine load
b. Heavy eng;ine load
c. High engine speed
d. None of these
The function of a charging system in an automobile is to
a. Supply elecfric power
b. Convert mechanical energy into electrical energy
c. Continually recharge the battery
d. Partly convert engine power into electric power
The number of diodes used in alternator for rectification from AC to DC is / are ........
a. 1 b. 2 c. 4 d. 6
The charging voltage at the start of the engine is than when the engine is running on load.
a. Higher
b. Lower
c. Equal
d. Any one of these
The high resistance in an alternator output circuit is often caused by .......
a. A bad regulator
b. A shorted diode
c. Loose or corroded connection
d. None of these
The ratio between the number of teeth on the starter motor pinion gear and the engine fly wheel ri.ng gear is about
a. 1:1 b. 1:5 c. 1 : 15 d. I : 100
The magnetic field required for starting motor operation is provided by the .........
a. Armature
b. Field windings
c. Solenoid
d. None of these
If starter motor spins but does not engage flywheel teeth and does not start the engine, the problem is most likely caused by a bad
a. Magnetic switch
b. Over running clutch
c. Positive battery cable
d. Ignition switch
The colour of tail light in a car is .........
a. White
b. Amber
c. Green
d. Red
The typc of reflector used for automobile head lamp is —
a. Parabolic
b. Hyperbolic
c. Spherical
d. Circular
The stop lights are also known as ..........
a. Tail lights
b. Brake lights
c. Indicator light
d. Fog light
The frequency of flashing light per minute in a turn indicator is about .......
a. 8
b. 80
c. 800
d. None of these
In a horn assembly which of the following part vibrates around 2000 vibrations per second?
a. Diaphragm
b. Tone disc
c. Armature
d. Contact points
A 12 volts windshield wiper motor consumes about .......... ampere of current under normal operation.
a. 0-1 b. 3-4 c. 10- 15 d. 20 - 30
The purpose of air conditioning a car is to confrol —
a. Temperature and pressure
b. Pressure and humidity
c. Humidity and temperature
d. Temperature, pressure and humidity
Which of the following should be cold during normal operation of the air conditioning system?
a. Compressor
b. Condenser
c. Receiver and drier
d. Evaporator
Which refrigerant is commonly used in modern automobile air-conditioning system?
a. R- 12
b. R- 22
c. R- 134a
d. R- 134
The purpose of corrugated fins used in condenser and evaporator is to
a. Trap insects and foreign objects, thus preventing them from entering the engine compattment
b. Control the air flow which passes through the condenser or evaporator
c. Increase the surface area, thus increasing heat exchange performance
d. Reinforce the heat exchanger
Which of the following sensor data will the automatic air-conditioning system use to operate the recirculation control motor?
a. Vehicle speed
b. In-car and outside temperatures
c. Engine oil temperature
d. Evaporator temperature
What is/are the causes of wind shield wiper motor running sluggishly?
a. Contact breaker gap is not correct
b. Binding in spindle or gear
c. Excessive blade pressure
d. All of these
What may be the causes if fuel gauge needle always remains at empty?
a. Defective gauge
b. Float arm sticking
c. Float punctured
d. All of these
The important parameter that can be controlled by electronic engine management system are
a. Air fuel ratio
b. Ignition and Injection timings
c. Idle speed
d. All of these
As per service manual recommendations the level of engine oil should be checked when the engine is .......
a. Cold
b. Wormed up
c. Hot
d. Very hot
Which of the following does not come under Vehicle Safety Technology?
a. Air bags
b. Remote key less entry system circuit
c. Tyre pressure monitoring system
d. Night vision Assist
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