Explore topic-wise MCQs in Automobile Engineering.

This section includes 315 Mcqs, each offering curated multiple-choice questions to sharpen your Automobile Engineering knowledge and support exam preparation. Choose a topic below to get started.

51.

If the oil level in the oil pan of the engine is maintained above the gauge mark, the likely damage it may cause is

A. Engine fuming
B. Carbon deposits
C. Blue colour in exhaust
D. All of the above
E. None of the above
Answer» E. None of the above
52.

Boiling range of kerosene is

A. 50 to 100?C
B. 100 to 150?C
C. 150 to 300?C
D. 350 to 500?C
E. None of the above
Answer» D. 350 to 500?C
53.

The most widely used brakes are operted

A. Electrically
B. Hydraulically
C. By vacuum
D. Combination of (A) and (C)
E. Mechanical
Answer» C. By vacuum
54.

In a S.I. engine high air velocity through air hom may be of the order of

A. 100 m/s
B. 10 m/s
C. 1 m/s
D. 5 m/s
E. 50 m/s
Answer» B. 10 m/s
55.

Cetane number of Diesel oil normally available in market is in the range.

A. 75 -- 80
B. 60 -- 65
C. 90 -- 105
D. 90 -- 100
E. 45 -- 50
Answer» F.
56.

Efficiency of an IC engine is normally of the order of

A. 30-35%
B. 50-60%
C. 10-15%
D. 80-90%
E. Alcohol
Answer» B. 50-60%
57.

In a four stroke SI engine the inlet valve opens

A. at TDC and closes at BDC
B. 10? before TDC and closes 10? after BDC
C. 10? before TDC and closes 10? after BDC
D. 10? before TDC and closes 50? after BDC
E. None of the above
Answer» E. None of the above
58.

Quality of diesel oil can be expressed in terms of cetane number and also

A. aniline point
B. API gravity
C. SAE number
D. diesel index
E. None of the above
Answer» C. SAE number
59.

Cetane number of a Diesel fuel is measure of

A. Ignition quality
B. Viscosity
C. Volatility
D. Delay period
E. A.P.I. specific gravity
Answer» E. A.P.I. specific gravity
60.

The ignition coil acts as

A. A capacitor
B. An inductor
C. A RC circuit
D. A step up transformer
E. A step down transformer
Answer» E. A step down transformer
61.

If a spark plug does not fire, the probable cause could be

A. Cracked porcelain
B. Carbonized porcelain
C. Moisture or dirt accumulation on porcelain
D. Weak ignition coil
E. Any of the above
Answer» C. Moisture or dirt accumulation on porcelain
62.

In case of a Petrol engine, the spark plug should produce the spark

A. exactly at the end of compression stroke
B. slightly before the end of compression stroke
C. slightly after the end of exhaust stroke
D. none of the above
E. None of the above
Answer» C. slightly after the end of exhaust stroke
63.

In automobile, probable cause for ineffective brakes could be

A. Grease on lining
B. Excessive lining wear
C. Drums scored
D. Any of above
E. None of the above
Answer» E. None of the above
64.

High gum content in petrol may result in

A. detonation
B. misfiring
C. clogging of carburettor
D. none of the above
E. None of the above
Answer» D. none of the above
65.

In automobile ignition system contact breaker is used for

A. Opening and closing the primary circuit
B. opening and closing the secondary circuit
C. increasing the duration of spark
D. increasing the intensity of spark
E. None of the above
Answer» B. opening and closing the secondary circuit
66.

Acid used in automobile battery is

A. Hydrochloric acid
B. Sulphuric acid
C. Dilute nitric acid
D. Concentrated nitric acid
E. Hydrofluoric acid
Answer» C. Dilute nitric acid
67.

Which instrument is used to measure specific gravity

A. Thermometer
B. Hydrometer
C. Hydrometer
D. Anemometer
E. None of the above
Answer» D. Anemometer
68.

In spark plug the gap between the electrodes is

A. 10 mm
B. around 5 mm
C. around 1 mm
D. less than 1 mm
E. None of the above
Answer» E. None of the above
69.

The turbulence in diesel engine ensures to

A. Increase the compression pressure
B. Reduce the engine vibrations
C. Bring the fuel quickly in contact with air
D. Increase the fuel consumption
E. Increase the volumetric efficiency
Answer» D. Increase the fuel consumption
70.

In an automobile the probable cause for dragging brakes could be

A. Lack of clearance
B. Drums out of round
C. Loose wheel bearings
D. Weak retracting spring
E. Any of the above
Answer» F.
71.

The stationary part of the Wankel engine has an inner contour of

A. elliptical section
B. two lobed epitrochoid section
C. four lobed epitrochoid section
D. none of the above
E. None of the above
Answer» C. four lobed epitrochoid section
72.

Executive clutch clearance caused by improper adjustment or wear of sliding sleeve, generally results in

A. Clutch slip
B. Clutch failure to disengage
C. Clutch plate over heating
D. Uneven clutch engagement
E. Any of the above
Answer» C. Clutch plate over heating
73.

Diesel engines are generally preferred for road transport these days because of low

A. Maintenance cost
B. Operating cost
C. Initial cost
D. Prime cost
E. Manufacturing cost
Answer» C. Initial cost
74.

The device used to measure the clearance between the valve and tappet of an internal combustion engine is

A. Slip gauge
B. Thickness gauge
C. Feeler gauge
D. Snap gauge
E. Micrometer
Answer» D. Snap gauge
75.

Which of the following symptoms will not show that the combustion is necessarily complete or not?

A. Presence of free carbon in exhaust
B. Presence of carbon monoxide in the exhaust
C. Presence of oxygen is the exhaust
D. Presence of nitrogen in the exhaust
E. None of the above
Answer» E. None of the above
76.

In a 2-stroke S.I. engine

A. exhaust and transfer (inlet) ports open and cloe simultaneously
B. exhaust port opens 5? before the transfer port and closes 5? after the transfer port
C. exhaust port opens 5? ahead of the transfer port but both ports close simultaneously
D. none of the above
E. None of the above
Answer» C. exhaust port opens 5? ahead of the transfer port but both ports close simultaneously
77.

The condenser in ignition circuit of an S.I. engine

A. increases the battery voltage
B. decreases the current from battery
C. avoids arcing at contact breaker
D. none of the above
E. None of the above
Answer» D. none of the above
78.

When fully charged, the terminal voltage per cell for a battery is

A. 1.5 volts
B. 2.7 volts
C. 1.7 volts
D. 6 volts
E. 12 volts
Answer» C. 1.7 volts
79.

The phenomenon that causes pressure waves resulting in vibration of structure, rough running and melting of piston is

A. detonation
B. pre-ignition
C. knocking
D. none of the above
E. None of the above
Answer» B. pre-ignition
80.

Over heating of a two stroke air cooled engine cannot be due to

A. Incorrect ignition or valve timing
B. Too lean fuel mixture
C. Lack of cylinder jacket cooling water
D. Partly restricted exhaust system
E. Restricted air cleaner
Answer» D. Partly restricted exhaust system
81.

Stratification of charge is achieved by

A. use of two or more carburettors
B. locating two spark plugs on a cylinder
C. incorporating an auxiliary chamber
D. combining inlet and exhaust valves into a single unit
E. None of the above
Answer» D. combining inlet and exhaust valves into a single unit
82.

Balls for a ball bearing are made of

A. Stainless steel
B. Carbon chrome steel
C. High speed steel
D. Mild steel
E. Stainless steel
Answer» C. High speed steel
83.

The escape of burned gases from the combustion chamber past the pistons and into the crank case is called

A. Gas-loss
B. Crank case explosion
C. By-pass
D. Blow-by
E. Passed gas
Answer» E. Passed gas
84.

In order to engage securely and prevent dragging the clearance between release bearing and release collar in a clutch is usually

A. 30 - 35 mm
B. 20 - 25 mm
C. 40 - 50 mm
D. 2 - 3 mm
E. 10 - 15 mm
Answer» E. 10 - 15 mm
85.

The efficiency of an oil bath type air cleaner is usually

A. 90%
B. 50%
C. 60%
D. 99%
E. 80%
Answer» E. 80%
86.

LPG mainly consists of

A. Methane and ethane
B. Propane and butane
C. Petrol and diesel
D. Hexane and butadiene
E. None of the above
Answer» C. Petrol and diesel
87.

In a S.I. engine the intake valve closes

A. 35? to 80? after BDC
B. 25? to 80? before BDC
C. At TdDC
D. 10? to 20? before
E. At BDC
Answer» B. 25? to 80? before BDC
88.

For the best utilization of fuel, in the engine cylinder, the air supply should be

A. About 10% surplus
B. 15 to 20 percent deficient
C. About 25% surplus
D. 5 to 10 percent deficient
E. Chemically correct
Answer» B. 15 to 20 percent deficient
89.

Which one of the following is a correct statement

A. the exhaust valve of a four stoke I.C. engine should open exactly at the end of expansion stroke
B. in actual practice, inlet valve of a four stroke I.C. engine should open exactly at the start of suction stroke
C. the inlet valve remains open approximately for 180?
D. valve overlap is the angle during which both the inlet and exhaust valves remain open simultaneously
E. None of the above
Answer» E. None of the above
90.

In a Diesel engine the duration between the time of injection and the time of ignition is called

A. Spil cut off
B. Delay period
C. Period of injection
D. Period of ignition
E. None of the above
Answer» C. Period of injection
91.

A heat-treated glass generally used in automobiles upon cracking bursts into

A. Sharp edged fragments
B. Small particles
C. Does not disintegrate
D. Either of the above
E. None of the above
Answer» C. Does not disintegrate
92.

The function of Diesel feed pump (when ever provided) is to

A. Pump the fuel to the injector
B. Pump the fuel from the tank into the injection pump
C. Send back the fuel from the injector into the tank
D. Pump the oil into the main gallery
E. Pump the fuel from the injection pump to the injector
Answer» C. Send back the fuel from the injector into the tank
93.

Clutch slippage while clutch is engaged is particularly noticeable

A. During acceleration
B. At low speed
C. While starting the engine
D. During idling
E. During braking
Answer» B. At low speed
94.

Circumferential grooves on tyres

A. Lessen the danger of skidding
B. Increase load carrying capacity
C. Provide good traction
D. Remove any stones etc. from sticking to the tyre
E. All of the above
Answer» B. Increase load carrying capacity
95.

The knocking in S.I. engines can be prevented if the end mixture is having

A. high density
B. medium density
C. low density
D. none of the above
E. None of the above
Answer» D. none of the above
96.

Bead of a tyre constitutes

A. metal foundations of the tyre
B. side walls of the tyre
C. shoulder region
D. none of the above
E. None of the above
Answer» B. side walls of the tyre
97.

When not in use, the self-discharge of an automobile battery in dry weather is usually

A. 0.5 to 1%
B. 7 to 7.5%
C. Not more than 10%
D. Not more than 15%
E. Any of the above
Answer» B. 7 to 7.5%
98.

Dirt or gum in fuel nozzle or jets may cause

A. Excessive fuel consumption
B. Uneven engine speed
C. Smoky black exhaust
D. Lack of engine power
E. White exhaust
Answer» D. Lack of engine power
99.

A thermostat is provided in automobile engines for

A. Controlling the temperature of the piston
B. Regulating the temperature of lubricating oil
C. Regulating the temperature of suction air
D. Regulating the temperature of haust gases.
E. Controlling the temperature of the cooling system
Answer» F.
100.

The probable cause for uneven wear of tyres for a truck could be

A. Low tyre pressure
B. Excessive camber
C. Tyres overloaded
D. Incorrect castor
E. Any of the above
Answer» F.