Dental Equipment Maintenance Technician - question paper and answer key


Question Code: 220/2023 

Medium of Question- English 

Name of Post: Dental Equipment Maintenance Technician 

Department: Health Services 

Cat. Number: 525/2022

1. How many numbers of cuts in a 250 mm flat bastard double cut file over a length in 1 cm ?

A) 7.1
B) 12
C) 8
d) 10

2. Which is the angle of an edge of a triangular file ?
 A) 90 degree
 B) 60 degree
 C) 30 degree
 d) 45 degree

3. Which is the most suitable pitch of a hack-saw blade cutting mild steel or cast iron ?
 A) 1.8 mm
 B) 0.8 mm
 C) 1.4 mm
 d) 1.0 mm

4. While chipping, the clearance angle is the angle between
 A) The working surface of the job and the top surface of the cutting edge of chisel
 B) The working surface of the job and the bottom surface of the cutting edge of chisel
 C) The surface at right angle to the cutting edge of chisel and the working surface of the job
 d) The point angle of the chisel and the working surface of the job

5. Which punch is used to locate the drill bit ?
 A) Prick punch
 B) dot punch
 C) Centre punch
 d) None of the above

6. In the following which is not the use of atry square ?
 A) measuring right angle
 B) Checking squareness
 C) marking straight line at 90 degree against an edge
 d) Setting work-piece at 90 degree angle

7. Which is the symbol conventionally used for resinoid bond ?
 A) ‘V’
 B) ‘R’
 C) ‘B’
 d) ‘E’

8. Which hammer is used for hammering inside curves for bending ?
 A) Ball-peen hammer
 B) Straight-peen hammer
 C) Sledge hammer
 d) Cross-peen hammer

9. Which head is used to set at any required angle in the combination set ?
 A) Square head
 B) Protractor head
 C) Centre head
 d) Rule

10. What is the accuracy of the surface of lapped and machined surface plate ?
 A) 0.001 mm
 B) 0.015 mm  
 C) 0.025 mm
 d) 0.0025 mm

11. Which of the following statement is/are correct about BSW thread ?
 i. BSW thread has an included angle of 55°.
 ii. depth of the thread is 0.6134 × Pitch.
 A) Only i
 B) Only ii
 C) All of the above (i and ii)
 d) Both i and ii are not correct

12. Which of the following statement is/are correct about BA thread ?
 i. BA thread has an included angle of 47.5°.
 ii. BA threads are used in small screws of electrical appliances, watch screws, screws of scientific apparatus.
 A) Only i
 B) Only ii
 C) All of the above (i and ii)
 d) Both i and ii are not correct

13. What is the included angle of metric acme thread ?
 A) 29°
 B) 30°
 C) 60°
 d) 45°

14. Which of the following thread, one flank is perpendicular to the axis of the thread and the other flank is at 45° ?
 A) BA thread
 B) Trapezoidal threads
 C) Worm thread
 d) Buttress thread

15. Which of the following statement is/are correct about pitch diameter of a thread ?
 i. It is the smallest diameter formed after an external thread is cut.
 ii. It is the largest diameter over which a thread is cut in the case of an external thread.
 iii. It is the diameter of an imaginary cylinder which passes through the thread such that the width of the space is equal to the width of the thread.
 A) Only i
 B) Only ii
 C) Only iii
 d) All of the above (i, ii and iii)

16. Which of the following statement is/are correct about square and trapezoidal threads ?
 i. Square and trapezoidal threads have more cross-sectional area than ‘V’ threads.
 ii. Square and trapezoidal threads are more suitable to transmit motion or power than ‘V’ threads.
 iii. Square and trapezoidal threads are not used for fastening purposes.
 A) Only i and iii
 B) Only ii and iii
 C) Only i and ii
 d) All of the above (i, ii and iii)

17. Which of the following is the horizontal distance from a point on one thread to the corresponding point on the adjacent thread measured parallel to the axis ?
 A) Crest  
 B) Root
 C) Pitch
 d) Flank

18. When a single helix is making a screw, it is called
 A) Single start thread
 B) multi-start threads
 C) Knuckle thread
 d) Worm thread

19. Which of the following statement is/are correct about multi-start threads ?
 i. In multi-start threads, the lead of the helix increased without increasing the pitch.
 ii. lead = Pitch × Number of starts in multi-start threads.
 iii. A multi-start thread makes it possible to keep the depth of thread less and provides a rapid axial movement of the screws.
 A) Only i and iii
 B) Only ii and iii
 C) Only i and ii
 d) All of the above (i, ii and iii)

20. Which of the following is the surface connecting the crest and the root of a thread ?
 A) depth of thread
 B) Flank
 C) Clearance
 d) Helix

21. One kWh of energy equals nearly
 A) 4186 J
 B) 860 kcal
 C) 735.5 W
 d) 1000 W

22. Induction watt hour meters are free from __________ errors.
 A) Frequency
 B) Creeping
 C) Phase
 d) Temperature

23. A coil has an inductance of 1 Henry, if current changing at the rate of 2A/sec induces
 A) Half a volt in it
 B) Two volt in it
 C) One volt in it
 d) Two volt in another coil

24. To convert a simple meter into a voltmeter, the resistor has to be connected in
 A) Shunt
 B) One shunt and one series
 C) Series
 d) Vertical

25. Which of the following variety of copper has the best conductivity ?
 A) Hard drawn copper
 B) Pure annealed copper
 C) Induction hardened copper
 d) Copper containing traces of silicon

26. A moving iron instrument can be used for
 A) AC only
 B) lux meters
 C) dC only
 d) Both AC and dC

27. Which resistor has negative temperature co-efficient ?
 A) Thermistor
 B) Sensistor
 C) ldR resistor
 d) Varistor

28. The resistance between the opposite faces of a meter cube of a material is known as
 A) Resistance
 B) Conductance
 C) Resistivity
 d) Conductivity

29. In a capacitor, the electric charge is stored in
 A) Both plates and dielectric
 B) metal plates
 C) dielectric
 d) None of the above

30. Why the ohm meter is graduated with non-linear scale ?
 A) Resistance is inversely proportional to the square of current
 B) Voltage is directly proportional to resistance
 C) Voltage is directly proportional to the square of current
 d) Current is inversely proportional to resistance

31. Which of the following is a ferrous metal ?
 A) Copper
 B) Cast iron
 C) Zinc
 d) Brass

 32. Steel is an alloy of iron and carbon. How much is the maximum quantity of carbon content in steel ?
 A) 1.5%
 B) 2.5%
 C) 3.5%  
 d) 2.75%

 33. What is meant by creep ?
 A) Property of breaking material without much permanent deformation
 B) Failure of a material caused under repeated or fluctuating loads
 C) The resistance of a material to elastic deformation
 d) The slow and continuous deformation of a material under steady load

 34. What is the melting point of lead ?
 A) 426°C
 B) 396°C
 C) 326°C
 d) 512°C

 35. Which of the following is an Aluminium alloy ?
 A) Gun metal
 B) y-Alloy
 C) Bell metal
 d) Nickel silver

 36. Which of the following is not the property of zinc ?
 A) It resists corrosion
 B) Good conductor of heat and electricity
 C) It melt at 231.5°C
 d) It is a bluish white metal

 37. Which of the following is measure of stiffness ?
 A) modulus of elasticity
 B) modulus of plasticity
 C) Resilience
 d) Toughness

 38. What is the composition of Brass ?
 A) Copper and zinc
 B) Copper and tin
 C) Zinc and tin
 d) Copper and nickel

 39. Which of the following material has the maximum ductility ?
 A) Zinc
 B) mild steel
 C) Aluminium
 d) Copper

40. What is the function of lead as an alloying element ?
 A) To improve strength and toughness
 B) To increase the elastic limit of steel
 C) To improve machinability
 d) To improve hardness

41. Which of the following is a part of Taly-surf ?
 A) Stylus
 B) motor race
 C) Analyser
 d) All of the above

42. Roughness value 0.2 to 0.8 microns is indicated by which symbol ?
 A) One inverted triangle
 B) Two inverted triangles
 C) Three inverted triangles
 d) Four inverted triangles

43. When a circle is added to the basic symbol of two legs of unequal length inclined at approximately 60°, what is meant by the surface symbol indication ?
 A) material removal by machining is required
 B) The material removal is not permitted
 C) material addition is required
 d) Any machining method can be used

44. Which of the following process give maximum surface finish ?
 A) Honing
 B) Sand casting
 C) Burnishing
 d) lapping

45. The lines or patterns on the work surface caused by the movement of the cutting
tool is called
 A) Roughness
 B) Waviness
 C) Surface texture
 d) lay

46. The quantity of heat required to change unit mass of substance completely from one
state in to another at constant temperature is
 A) Specific heat
 B) Heat capacity
 C) Latent heat  
 D) Molar specific heat

47. What is the unit of heat in SI system ?
 A) Calorie
B) Joule
C) Ampere
d) Hertz
48. The mode of heat transfer which doesn’t require a medium is
 A) Radiation
 B) Conduction  
 C) Convection
 d) Friction

49. The SI unit of pressure is
 A) Erg  
 B) Watt
 C) Pascal
d) Newton

50. In Fahrenheit scale, the boiling point is fixed at
 A) 25°F
 B) 100°F
 C) 200°F  
 d) 212°F

51. The pressure measured greater than atmospheric pressure is called
 A) Vacuum pressure
 B) Gauge pressure
 C) Absolute pressure
 d) Atmospheric pressure

52. The temperature range of oxy-acetylene flame is
 A) 1825°C to 1875°C
 B) 2400°C to 2700°C
 C) 2700°C to 2800°C  
 d) 3100°C to 3300°C

53. The instrument used to measure very high temperature of furnace is
 A) Thermometer
 B) Pyrometer
 C) Barometer
 d) Technometer

54. The metal joining process in which the work-pieces are not heated is called
 A) Brazing  
 B) Welding
 C) dip brazing
 d) Soldering

55. The most active soldering flux group is
 A) Inorganic fluxes
 B) Resin fluxes
 C) Organic fluxes
 D) Both B) and C)

56. Which type of oxy-acetylene gas flame is widely used for welding mild steel material ?
 A) Oxidising flame
 B) Neutral flame
 C) Carburising flame
 D) All of the above

57. In leftward welding technique of oxy-acetylene gas welding, the blow pipe is held at an angle between
 A) 10° to 20°
 B) 30° to 40°
 C) 40° to 50°
 d) 60° to 70°

58. The type of AC arc welding transformer is
 A) Step up transformer
 B) Step down transformer
 C) Auto transformer
 d) Power transformer

59. Hydrochloric acid is used as flux for soldering which material ?
 A) Steel
 B) Brass
 C) Zinc
 d) lead

60. Which among the following is not a method of Brazing ?
 A) Electroslag Brazing
 B) Induction Brazing
 C) Furnace Brazing
 d) Torch Brazing

61. Which of the following statements is/are correct about pattern making in casting ?
 i. Wood is the most common material for making patterns for castings.
 ii. When a metal pattern is cast itself using a wooden pattern, then the wooden pattern is called a dummy pattern.
 iii. A good pattern is one which can be easily worked, shaped and joined and should be light in weight.
 iv. Plastics are not used as pattern material for casting.
 A) Only ii and iii
 B) Only i and iv
 C) Only i, ii and iii
 d) Only i and iii

62. Arrange the below stages of casting as per their order of manufacturing sequence.
 a. Testing and inspection
 b. melting and casting
 c. moulding and core making
 d. Fettling
 e. Pattern making
 A) e – d – c – b – a
 B) a – e – c – b – d
 C) e – c – b – d – a
 d) c – d – b – e – a

63. match list – I with list – II below :

 A) c d b a
 B) b a d c
 C) b d a c
 d) d c b a

64. Which of the following statements is/are false about sand casting ?
 i. The intermediate mould section between cope and drag is known as cheek.
 ii. Cope refers to the lower half containing the bottom half of the pattern.
 iii. drag refers to the upper half containing the top half of the pattern.
 iv. The proper design of tapered sprue is necessary to avoid aspiration effect.
 A) i and iv only
 B) ii and iii only
 C) i, ii and iii only
 d) none of these

65. Which statement is true about hot chamber die casting ?
 A) In hot chamber die casting, the melting unit constitutes an integral part of the process.
 B) In hot chamber die casting, the mould is submerged in the molten metal.
 C) In hot chamber die casting, the entire machine is heated.
 d) In hot chamber die casting, the molten metal is brought and poured into the die casting machine with the help of ladles.

66. Which statement is false about centrifugal casting ?
 A) Centrifugal casting methods are classified as true-centrifugal casting, semicentrifugal casting and centrifuged casting.
 B) They have more or less a symmetrical configuration on their outer contour.
 C) To form the internal shape; pressure is generally obtained by compressed air or hydraulically.
 d) The use of gates, feeders and cores is eliminated, making the method less expensive.

67. Which among the following is a limitation of sand casting ?
 A) Economical for low-volume production
 B) Extreme complexity is possible
 C) most direct route from pattern to casting
 d) The product gives a rough surface

68. Pump is used for increase the pressure in
 A) Pipe lines
 B) Section pipe
 C) Vent pipe
 d) Hume pipe

69. Select the Reciprocating pumps are following
 A) Simple hand operated
 B) Single acting
 C) A) and B)
 d) Centrifugal mono block

70. Compressed air pump can lift water from a depth of _________ meter.
 A) 50
 B) 100
 C) 130
 d) 150

71. Priming is a process of filling up water in the
 A) Casing
 B) Suction pipe
 C) Casing and suction pipe
 d) None of these

72. What are the main components of a centrifugal pump ?
 A) Impeller
 B) Prime mover
 C) delivery pipe
 d) A), B) and C)

73. In a vernier caliper, movable jaws are the parts of which unit ?
 A) Fixed jaw
 B) Vernier slide
 C) Beam
 d) main scale

74. In which part of micrometer one end forms measuring face and the other end is threaded and the tapered nose is fitted on it ?
 A) Ratchet stop
 B) Barrel
 C) Spindle
 d) Thimble

75. Which instrument is used to measure sizes from the lower plane with the help of an offset scriber ?
 A) Vernier height gauge
 B) Vernier scale
 C) Vernier caliper
 d) depth micrometer

76. What is the least count of depth micrometer ?
 A) 0.02 mm
 B) 0.001 mm
 C) 0.01 mm  
 d) 0.1 mm

77. Which instrument is used to measure the diameter of holes and the distance between internal parallel surfaces like slots ?
 A) depth micrometer
 B) Inside micrometer
 C) depth bar
 d) Vernier caliper

78. In which instrument the distance or the measurements are read from lCd/lEd display ?
 A) digital caliper
 B) depth gauge
 C) Vernier caliper
 d) dial caliper

79. In a vernier caliper, the main scale divisions (9 mm) are divided into 10 equal parts in the vernier scale. What is the least count of this vernier caliper ? Here one main scale division is (1 mm).
 A) 0.02 mm
 B) 0.1 mm
 C) 0.01 mm
 d) 0.001 mm

80. Which device is fitted on micrometers to ensure uniform pressure between the measuring faces of the micrometer while measuring ?
 A) Anvil
 B) Spindle
 C) Ratchet stop
 d) Barrel

81. Which is the personal safety ?
 A) Keep the machine clean
 B) Concentrate on your work
 C) Keep the gang way and floor clean
 D) Sweep away the metal cuttings

82. Which is the immediate life saving procedure ?
 A) First aid
 B) Call a doctor
 C) Intensive care
 d) medical treatment
83. What ‘A’ denotes in ABC of ‘First aid’ ?
 A) Air way
 B) Accident
 C) Absent mind
 d) Avoid accident

84. Which of the following activity to be performed for better up keep of working environment ?
 A) Crack practical jokes while on work
 B) Cleaning the shop floor
 C) leave the machines which is in motions
 d) do not use adequate light in the workshop

85. What is the shape of warning signs ?
 A) Circular
 B) Triangular
 C) Square of oblong
 d) Square

86. What is the ratio of 4 kg to 800 grams ?
 A) 5 : 1
 B) 4 : 8
 C) 8 : 4
 d) 2 : 4

87. How many millimetres are there in 12 inch ?
 A) 30.48 mm
 B) 304.8 mm
 C) 3.048 mm
 d) 40.48 mm

88. divide : 20/31 ÷ 15/62

A)2 4/3 

B)2 3/2  

C)2 1/3 

D) 2 2/3

89. What is the percentage of copper in the casting if the weight of copper is 42.3 kg and weight of tin is 2.7 kg ?
 A) Cu 98%
 B) Cu 96%
 C) Cu 94%
 d) Cu 92%

90. What is the length of copper wire, if the copper wire weights 8 kg, density of copper is 8.9 g/cm3 and cross-sectional area is 0.636 cm2 ?
 A) 1400.10 cm
 B) 1300.10 cm
 C) 1313.33 cm
 d) 1413.33 cm

91. Two turners need three days to produce 20 pieces. How long does it takes for 6 turners to produce 30 such pieces ?
 A) 2 days
 B) 2.5 days
 C) 1.5 days
 d) 2.25 days

92. A cylindrical tank 2 m diameter × 3.5 m deep is filled with petrol. Find the weight of petrol in tonnes, assume density of petrol is 720 kg/m3.
 A) 7900.8 Tonnes
 B) 7912.8 Tonnes
 C) 7952.8 Tonnes
 d) 7940.8 Tonnes

93. The lower limit of a dimension, stated as 23H7 in a drawing is
 A) 23.70
 B) 22.70
 C) 23.00
 d) 22.30

96. A basic hole means
 A) Upper deviation is zero
 B) lower deviation is zero
 C) Both A) and B)
 d) None of the above

97. The relation between mating parts in an assembly is termed as
 A) link
 B) Joints
 C) Fits
 d) mechanism

98. The difference between the size of manufactured product and the corresponding nominal size is termed as
 A) Allowance
 B) Tolerance
 C) Actual deviation
 d) minimum deviation

99. Which of the following statements is correct regarding ‘‘minimum Clearance’’ ?
 A) difference between maximum size of hole and minimum size of shaft.
 B) difference between maximum size of hole and maximum size of shaft.
 C) difference between minimum size of hole and minimum size of shaft.
 d) difference between minimum size of hole and maximum size of shaft.

100. If the allowance of 0.03 mm for clearance is given and the shaft diameter is 18 mm, find the design size.
 A) 18.03 mm
 B) 17.97 mm
 C) 17.03 mm
 d) 18.97 mm

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