PSC Junior Instructor mechanic Motor Vehicle Model Questions and Answers

51. Which of the following gear boxes have lesser mechanical efficiency?
(A) Synchromesh
(B) Constant mesh
(C) Sliding mesh
(D) All of these
Answer: C

52. Alloy steels are generally quenched in
(A) Water
(B) Oil
(C) Brine
(D) Ice
Answer: B

53. The fastener used to transmitting torque from a rotating shaft to a hub or vize versa
(A) Circlip
(B) Locking ring
(C) Tab washer
(D) Key
Answer: D

54. Adjustment of FIP in which ensure equal time interval of fuel delivery to all engine cylinders
(A) Leak off
(B) Calibration
(C) Phasing
(D) Chattering
Answer: C

55. The process of continues releasing and applying of brake in an ABS is called
(A) Pressure modulation
(B) Pulse modulation
(C) Speed modulation
(D) None of these
Answer: A

56. Maximum boost pressure of a turbocharger is controlled by a
(A) EGR valve
(B) Waste gate
(C) Blow-off valve
(D) Pressure release valve
Answer: B

57. Annulus in an epicycle gear box is usually known as
(A) Ring gear
(B) Carrier
(C) Planet
(D) Sun gear
Answer: A

58. The length variation between leaf spring eyes by the oscillation of leaves are accommodate with the help of
(A) Centre bolt
(B) Shackle
(C) ‘U’ Clamp
(D) Bracket
Answer: B

59. Which among the following is a disadvantages of hypoid gear using in final drive?
(A) Low chassis height
(B) Smaller pitch overlap
(C) Rough running
(D) Less ground clearance
Answer: D

60. The steering sensor in an electronic power steering system consist of
(A) Torque and pressure sensor
(B) Torque and speed sensor
(C) Torque and rotation sensor
(D) Speed and rotation sensor
Answer: C

61. The percentage ratio between difference of vehicle speed and wheel speed to the vehicle speed is
(A) Velocity ratio
(B) Speed ratio
(C) Slip ratio
(D) Aspect ratio
Answer: C

62. In a disc brake caliper, the component act as a return spring to retract the piston
(A) Bleed screw
(B) Rubber sealing ring
(C) Disc
(D) Friction pads
Answer: B

63. Identify the horn relay with its marking
(A) HBR
(B) HRS
(C) BRS
(D) HBS
Answer: D

64. Location of an expansion valve in an automotive air conditioning is at
(A) Inlet side of evaporator
(B) Outlet side of evaporator
(C) Inside the evaporator
(D) Inlet side of condenser
Answer: A

65. The socket in which provided with a universal joint
(A) Deep
(B) Flex
(C) Standard
(D) None of these
Answer: B

66. The catalyst used for first stage conversion in a three – way convertor
(A) Vanadium
(B) Cerium
(C) Platinum
(D) Rhodium
Answer: D

67. Combustion knock in a CI engine is generally known as
(A) Diesel knock
(B) Diesel lock
(C) Both (A) and (B)
(D) Detonation
Answer: A

68. Which of the following are provided to the crank shaft to the balancing of main journals?
(A) Crank arm
(B) Harmonic balancer
(C) Crank weight
(D) Crank pulley
Answer: C

69. Permissible range of particulate matters in the exhaust gas of a petrol engine as per Euro 4 emission standard is
(A) 0.14 gm/Km
(B) 0.08 gm/Km
(C) 0.05 gm/Km
(D) None of these
Answer: D

70. Oil additives which handle high temperature deposit such as gums and varnishes
(A) Dispersant
(B) Detergent
(C) Anti-scuff additives
(D) Anti foaming additives
Answer: B

71. In an alternator, the carbon brushes ride on the
(A) Commutator
(B) Rotor shaft
(C) Slip ring
(D) Field windings
Answer: C

72. Choose correct drive transmission from engine to gear box
(A) Fly wheel – cover – drive plate – driven plate
(B) Fly wheel – cover – driven plate – drive plate
(C) Fly wheel – driven plate – drive plate – cover
(D) Fly wheel – drive plate – driven plate – cover
Answer: A

73. As related to the automatic transmission, the friction loss in the manual transmission is
(A) Less
(B) Same
(C) More
(D) Much more
Answer: A

74. Separate carrier type rear axle casing is generally known as
(A) Split type
(B) Salisbury type
(C) Banjo type
(D) Integral carrier type
Answer: C

75. Which among the following springs have the greater energy storing capacity?
(A) Coil spring
(B) Torsion spring
(C) Leaf spring
(D) Rubber spring
Answer: D