Junior Instructor (Mechanic Auto Electrical and Electronics) - Question Paper and Answer Key

 Name of Post: Junior Instructor (Mechanic Auto Electrical and Electronics) 

Department: Industrial Training

Cat. No: 461/2021

Date of Test: 07.01.2023

Question Code: 002/2023


 1. ____________ is used to check warpage of an engine cylinder head.
 A) Straight edge ruler
 B) Dial gauge
 C) Plastic gauge
 D) V blocks

 2. An odometer is an instrument used to measure ___________ in automobiles.
 A) speed
 B) odour
 C) direction
 D) distance

 3. Which type of fire extinguisher is used for fire due to liquids ?
 A) class A
 B) class B
 C) class C
 D) class D

 4. Which among the following devices can be used to spot short circuits in the armature ?
 A) voltmeter
 B) ammeter
 C) growler
 D) multimeter

 5. The measuring device used to find the thickness of sheet metals is
 A) Steel rule
 B) Wire gauge
 C) Vernier caliper
 D) Feeler gauge

 6. A bolt of M24 × 2 means that
 A) the pitch of the thread is 24 mm and depth is 2 mm
 B) the nominal diameter of the bolt is 24 mm and the pitch is 2 mm
 C) the cross sectional area of the thread is 24 mm
 D) the effective diameter of the bolt is 24 mm and there are 2 threads per cm
7. The difference between the upper limit and lower limit of a dimension is called
 A) Basic size
 B) Nominal size
 C) Tolerance
 D) Actual size

 8. Which type of personal protective item can be used to protect eyes ?
 A) Cap
 B) Goggles
 C) Gloves
 D) Mask

 9. Which type of Energy Conservation Opportunity (ECOs) involves stopping of water leakage points ?
 A) Major energy conservation opportunities
 B) Medium energy conservation opportunities
 C) Extra major energy conservation opportunities
 D) Minor energy conservation opportunities

 10. The process for enlarging or finishing a previously drilled hole is known as
 A) Drilling
 B) Reaming
 C) Tapping
 D) Lapping

 11. Read the statements given below and choose the correct option.
 Statement A : The ignition spark occurs as the piston nears TDC at the end of the compression stroke.
 Statement B : The spark occurs while the intake and exhaust valves are closed.
 A) Statement A is correct
 B) Statement B is correct
 C) Both statements are correct
 D) Both statements are wrong

 12. A two stroke engine is normally equipped with a
 A) train valve
 B) poppet valve
 C) reed valve
 D) all of the above

 13. Connecting rod connects crankshaft and the
 A) Cylinder head
 B) Cylinder block
 C) Camshaft
 D) Piston

 14. Vibration damper is mounted on
 A) the front end of the crankshaft
 B) the back end of the crankshaft
 C) the front end of the camshaft
 D) none of these
15. Choose the correct statement.
 A) inlet and exhaust valves are of the same size
 B) the size of the inlet valve is more
 C) the size of the exhaust valve is more
 D) the size of the valves depends upon the capacity of an engine

 16. The purpose of the thermostat is to keep the engine
 A) hot
 B) cool
 C) at desired temperature
 D) none of the above

 17. Antiknock quality of gasoline is measured by
 A) oxidation number
 B) vaporization number
 C) octane number
 D) detonation number

 18. Read the statements given below and choose the correct option.
 Statement A : A plastic scraper can be used any gasket material from the head.
 Statement B : A reamer can be used to clean the valve guides.
 A) Statement A is correct
 B) Statement B is correct
 C) Both statements are correct
 D) Both statements are wrong

 19. The swept volume of a cylinder in an engine is
 A) cross sectional area × stroke
 B) cross sectional area / stroke
 C) total volume + clearance volume
 D) none of the above

 20. The distance between the centres of the front wheel is called
 A) Axle width
 B) Wheel base
 C) Track
 D) Turning circle

 21. In cars having rack and pinion steering, the gear rack is attached to
 A) relay rod
 B) pitman axis
 C) cross shaft
 D) tie rod

 22. The function of master cylinder is
 A) to increase pressure equally in all cylinders
 B) to increase pressure unequally in all cylinders
 C) to decrease pressure unequally in all cylinders
 D) to decrease power equally in all cylinders
23. The camber of leaf spring is
 A) The amount of bend that is given to the spring from the central line, passing through the eyes
 B) Distance between both eyes
 C) The vertical distance between middle of the main leaf to imaginary line connecting the two eyes of the spring
 D) Options A and B are correct
24. Slack adjuster is used in air brake system to adjust
 A) Scam
 B) Wheel cylinder
 C) Back plate eccentric
 D) Brake valve

 25. Identify which is not a type of frame ?
 A) conventional frame
 B) half-integral frame
 C) integral frame
 D) semi-integral frame

 26. Which transmission system member among the following helps to vary the leverage between engine and road wheels ?
 A) Clutch
 B) Gear box
 C) Propeller shaft
 D) Differential

 27. Normal force acting on the friction surface is greater than the axial force in the case of
 A) Cone clutch
 B) Single plate clutch
 C) Multi-plate clutches
 D) Wet clutch

 28. Which among the following is not supposed to be operated by the user ?
 A) Single plate clutch
 B) Multi-plate clutch
 C) Centrifugal clutch
 D) Semi centrifugal clutch
29. Gears in sliding mesh gear box are
 A) Cycloidal gears
 B) Worm gears
 C) Helical gears
 D) Spur gears

 30. The driving / driver shaft of the gear box is also known as
 A) Clutch shaft
 B) Lay shaft
 C) Counter shaft
 D) Main shaft

 31. The member which multiplies the torque in a torque converter is
 A) Impeller
 B) Turbine
 C) Planetary gear
 D) Stator

 32. In order to accommodate the variation in length, a propeller shaft must have
 A) Hooks joint
 B) Slip joint
 C) Leaf spring
 D) Torsional spring

 33. Which of the following member is used to hold the rear axle in position against side thrust ?
 A) Radius rod
 B) Thrust member
 C) Panhard rod
 D) Thrust spring

 34. Type of wheel desirable in racing cars is
 A) Magnesium alloy wheel
 B) Disc wheel
 C) Aluminium alloy wheel
 D) Wire wheel

 35. When loading a vehicle, the load distribution should be
 A) More at front wheels
 B) More at right wheels
 C) More at rear wheels
 D) Equal at all wheels

 36. In modern diesel engines pilot injection is aimed at
 A) Reducing noise
 B) Reducing NOx emissions
 C) Both A and B
 D) None of the above

 37. In CRDI system, the maximum pressure developed by the high pressure pumps is usually
 A) 200 bar
 B) 1600 bar
 C) 1200 bar
 D) 800 bar

 38. Switching speed of piezo injector is how many times than that of a solenoid valve
 A) two
 B) three
 C) four
 D) five

 39. In petrol electronic fuel injection system, the amount of fuel drawn by the fuel pump is
 A) same as the required
 B) half the required
 C) less than the required
 D) more than the required

 40. Which sensor is used to correct the air density variation with atmospheric temperature ?
 A) MAP sensor
 B) BARO sensor
 C) MAT sensor
 D) TPS sensor

 41. Which electronic unit gives signal to control IAC valve ?
 C) Solenoid

 42. How many petrol injection systems are there, according to the duration and timing of fuel injection ?
 A) Four
 B) Two
 C) Three
 D) Five

 43. Compared to First Generation Air Bags, Second Generation Air Bags inflates with
 A) More energy
 B) Less time
 C) More force
 D) Less force

 44. Which type of seat belt operates automatically with no action required by the vehicle’s occupant ?
 A) Passive restraint
 B) Retractor
 C) Active restraint
 D) Anchorage

 45. A high-speed CAN BUS communicates with a scan tool through which terminal(s) ?
 A) 4 and 16
 B) 6 and 14
 C) 7 and 15
 D) 2

 46. In an Air conditioning system, the subcooled liquid refrigerant flows from the receiver drier to
 A) Compressor
 B) Condenser
 C) Expansion Valve
 D) Blower

 47. Relative humidity for comfort levels is generally about
 A) 25%
 B) 70%
 C) 50%
 D) 60%

 48. The desiccant used inside the receiver for R-134a is
 A) Silica gel
 B) Zeolite
 C) Both A and B
 D) None of the above

 49. Ambient temperature sensor is fitted near the
 A) A/C controls panel
 B) Compressor
 C) Condenser
 D) Evaporator

 50. The greatest source of refrigerant leakage is
 A) Flexible hoses
 B) Schrader valves
 C) Connector seals
 D) Compressor seal

 51. Stoichiometric air fuel ratio of petrol by mass is nearly
 A) 15 : 1
 B) 20 : 1
 C) 7 : 1
 D) 30 : 1

 52. Compared to petrol, hydrocarbon emissions for Ethanol as a SI engine fuel is
 A) More
 B) Less
 C) Same
 D) Zero

 53. In the case of CI engines, the delay period decreases with
 A) Decrease in intake temperature
 B) Increase in injection advance angle
 C) Increase in compression ratio
 D) None of the above

 54. Combustion in the third stage is rapid in the case of
 A) Turbulent chamber
 B) M Combustion chamber
 C) Energy cell
 D) Pre Combustion chamber

 55. What is the basic fuel for a fuel cell ?
 A) Hydrogen
 B) Methanol
 C) Electricity
 D) Gasoline

 56. A 30 F capacitor is connected across a 400 V supply. If the reactance of the capacitor is 100 Ohms, the value of the current is
 A) 500 A
 B) 4000 A
 C) 4 mA
 D) 4A

 57. With given details of junction transistor, match the followings :
 1. joining P type germanium to N-P junction a. electrons
 2. joining N type germanium to P-N junction b. holes
 3. charge carriers in PNP junction c. PNP type
 4. charge carriers in NPN junction d. NPN type
 A) 1-d, 2-c, 3-b, 4-a
 B) 1-c, 2-d, 3-a, 4-b
 C) 1-b, 2-a, 3-d, 4-c
 D) 1-c, 2-d, 3-b, 4-a

 58. Which of the following statement is/are correct about Field Effect Transistor (FET) ?
 1. FET is unipolar.
 2. FET is not a majority carrier device.
 3. FET is having high impedance and better thermal stability.
 4. FET is having low impedance and poor thermal stability.
 A) only 1 and 3
 B) only 1 and 2
 C) only 2 and 3
 D) only 1 and 4

Correct Answer: B

 60. Zener diodes are available for voltage output control purpose with Zener voltages range from
 A) 1 to 10 V
 B) 3 to 100 V
 C) 1 to 50 V
 D) 1 to 300 V

 61. The applications of phototransistors includes
 1. photo-electric counting and speed indication
 2. automotive pollution control
 3. automotive parking and head light control
 4. automotive electronic ignition
 A) 1 and 2
 B) 2 and 3
 C) 3 and 4
 D) 1 and 3

 62. According to Fleming’s right hand rule, the direction of e.m.f. is represented by
 A) first finger of the right hand
 B) thumb of the right hand
 C) second finger held at right-angle to both the thumb and first finger
 D) second finger held inclined at an angle to both thumb and first finger

 63. A conductor carries a current of 1000 A at right-angles to a magnetic field having a density of 2 T. The force on the conductor with 2 m length is
 A) 1000 N
 B) 500 N
 C) 0.004 N
 D) 4000 N

 64. The number of ignition coils required for the eight cylinder V-8 engine with  distributorless ignition is
 A) 1
 B) 4
 C) 8
 D) 16

 65. The specific gravity of sulphuric acid of a lead-acid battery at 100% charge, 50% charge and 0% charge are
 A) 1.28, 0.64 and 0
 B) 1.68, 1.40 and 1.2
 C) 1.28, 0.80 and 0.5
 D) 1.28, 1.20 and 1.12

 66. Which of the following statement is/are correct about fully charged lead-acid battery ?
 1. The active material in positive plate is lead peroxide.
 2. The active material in positive plate is sponge lead.
 3. The active material in negative plate is sponge lead.
 4. The active material in negative plate is lead peroxide.
 A) only 1 and 3
 B) only 1 and 4
 C) only 2 and 3
 D) only 2 and 4

 67. The capacity increase of a lead-acid battery with 20-hour rate of discharge than  10-hour rate of discharge is approximately
 A) 100%
 B) 50%
 C) 5%
 D) 20%

 68. The electrolyte for lead-acid battery is prepared by mixing commercial concentrated sulphuric acid with distilled water approximately in the proportion of
 A) 8 parts of acid to 3 parts of water
 B) 3 parts of acid to 8 parts of water
 C) 5 parts of acid to 8 parts of water
 D) 8 parts of acid to 5 parts of water

 69. For trickle charging of lead-acid battery, the amount of charging rate used should be
 A) 10 to 25% of normal charging current
 B) 20 to 50% of normal charging current
 C) 2 to 5% of normal charging current
 D) 20 to 30% of normal charging current

 70. Match the followings for the ignition coil of automobile ignition system.
 a. number of turns in primary winding      1. about 20 S.W.G.
 b. number of turns in secondary winding  2. 15,000 to 20,000
 c. wire thickness of primary winding          3. about 40 S.W.G.
 d. wire thickness of secondary winding     4. 200 to 300
 A) a-2, b-3, c-1, d-4
 B) a-4, b-2, c-1, d-3
 C) a-1, b-2, c-3, d-4
 D) a-4, b-3, c-2, d-1

 71. In the battery coil ignition system, expression for the instantaneous value of primary current is

Correct Answer: B

 72. For automotive ignition system, match the followings :
 1. spark plug gap             a. 0.35 mm to 0.4 mm
 2. contact breaker gap         b. 0.60 mm to 1 mm
 3. dwell angle for 4-cylinder engine     c. 36° to 42°
 4. dwell angle for 6-cylinder engine     d. 48° to 52°
 A) 1-a, 2-b, 3-d, 4-c
 B) 1-b, 2-a, 3-d, 4-c
 C) 1-b, 2-a, 3-c, 4-d
 D) 1-c, 2-b, 3-d, 4-a

 73. With details regarding the spark plug, match the followings :
 1. Combustion chamber temperature             a. above 750°C
 2. Electrode temperature at which  pre-ignition occurs         b. 2400°C to 2600°C
 3. Electrode temperature at which  carbon or oil deposits     c. 500°C to 600°C
 4. Optimum electrode temperature                 d. below 300°C
 A) 1-b, 2-a, 3-d, 4-c
 B) 1-a, 2-b, 3-d, 4-c
 C) 1-a, 2-b, 3-c, 4-d
 D) 1-a, 2-c, 3-b, 4-d

 74. Which of the following statement is/are correct ?
 1. Flywheel magneto runs at the speed of camshaft.
 2. Dwell meter is used to measure spark plug gap.
 3. Feeler gauge or dwell meter is used to measure contact breaker gap.
 4. The maximum ignition advance by vacuum advance mechanism is 15 to 30 crankshaft degrees.
 A) only 1 and 2
 B) only 2 and 3
 C) only 3 and 4
 D) only 2 and 4

 75. The types of coil winding used in the armature of generator are
 A) star and lap winding
 B) wave and delta winding
 C) star and delta winding
 D) lap and wave winding

 76. The output voltage of an alternator not depends on
 A) rotor speed
 B) number of turns in starter winding
 C) field current
 D) current regulator

 77. In an electromagnet starter motor, the armature windings are made of
 A) many loops of heavy wire
 B) few loops of heavy wire
 C) few loops of thin wire
 D) many loops of thin wire

 78. The flywheel ring gear has about 15 times as many teeth as the pinion. When starter motor operates, if the armature spins at 3000 rpm, then the speed of the crankshaft is
 A) 450 rpm
 B) 200 rpm
 C) 2000 rpm
 D) 4500 rpm

 79. The primary function of an over running clutch in the starter motor is
 A) to transmit torque in both direction
 B) to increase cranking speed
 C) to prevent damage to armature from spinning at high speed
 D) to engage the starter pinion with ring gear

 80. The two types of fuses used in automobiles are
 A) catridge and blade
 B) breaker and catridge
 C) blade and breaker
 D) link and printed

 81. The mostly used firing order of six cylinder engine is
 A) 1-5-3-4-2-6
 B) 1-3-5-2-4-6
 C) 1-5-6-3-2-4
 D) 1-5-3-6-2-4

 82. Electronic ignition system consists of
 A) make and break mechanism
 B) solenoid switch
 C) contact breaker mechanism
 D) pulse generator or Hall-effect switch

 83. In third brush generator, the third brush is placed somewhere where the flux becomes
 A) stronger at the higher speeds due to armature reactions
 B) weaker at the higher speeds due to armature reactions
 C) weaker at the lower speeds due to armature reactions
 D) stronger at the lower speeds due to armature reactions

 84. Which of the following statement is correct about current voltage regulator ?
 A) Both current and voltage regulator operates simultaneously
 B) When battery charge is low, voltage regulator will operate
 C) When battery charge is low, current regulator will operate
 D) When battery charge is full, current regulator will operate

 85. Keyless entry systems can be operated by a small hand-held transmitter upto  distance of
 A) 100 m
 B) 200 m
 C) 50 m
 D) 10 m

 86. The vehicle location on the road can be shown by
 A) theft control system
 B) night vision system
 C) electronic navigation system
 D) lane detection system

 87. In the floor-type head light aiming system, the distance between the car and screen should be
 A) 15.2 m
 B) 7.6 m
 C) 25 m
 D) 7.6 feet

 88. The pitch of the electrically-operated horn sound is determined by
 A) horn button
 B) horn relay
 C) time period of pressing horn
 D) number of vibrations per second

 89. In a capacitor-discharge ignition, the spark occurs when
 A) the capacitor charges with battery voltage
 B) the capacitor charges with 50,000 V
 C) a transistor or switch closes the primary circuit
 D) a transistor or switch opens the primary circuit
90. The stationary magnetic field in the magnetic starter motor is produced by the
 A) brushes and commutator
 B) field windings in electromagnet or permanent-magnet
 C) armature windings
 D) relay or solenoid

 91. The unit of Density in SI unit is
 A) kg/m3
 B) m3/kg
 C) kg/m2
 D) N/m3

 92. Venturimeter is a device used to measure the
 A) Velocity of fluid
 B) Pressure of fluid
 C) Rate of flow of fluid
 D) Viscosity of fluid

 93. Newton’s law of viscosity states that
 A) Shear stress is directly proportional to the velocity
 B) Shear stress is directly proportional to velocity gradient
 C) Shear stress is directly proportional to shear strain
 D) Shear stress is directly proportional to the viscosity
94. Which one of the following is a type of actuator in a hydraulic system ?
 A) Pump
 B) Valve
 C) Strainer
 D) Cylinder

 95. The power source in Pneumatic system is
 A) Air receiver
 B) Compressor
 C) Valve
 D) Muffler

 96. Which one of the following welding processes uses non-consumable electrodes ?
 A) TIG welding
 B) Mig welding
 C) Manual arc welding
 D) Submerged arc welding

 97. In normalizing, components are cooled
 A) Using water
 B) Using oil
 C) In still air
 D) In furnace

 98. Which among the following is not a type of non-destructive testing ?
 A) Compression testing
 B) Visual testing
 C) Ultrasonic testing
 D) Eddy current testing

 99. Hooke’s law holds good upto
 A) Proportional limit
 B) Yield point
 C) Elastic limit
 D) Plastic limit

 100. Factor of safety is defined as the ratio of
 A) Working stress to ultimate stress
 B) Breaking stress to ultimate stress
 C) Ultimate stress to working stress
 D) Ultimate stress to breaking stress

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