1. A continuous linear indication along the edge of a new fillet weld would most likely
be a:
Correct : D. Heat affected zone hydrogen crack
2. Ferromagnetic material is:
Correct : C. Both (a) and (b)
3. The retentivity of a material describes:
Correct : D. The ability to retain the magnetic field
4. Which of the following can be magnetised?
Correct : D. All of the above
5. The magnetic field is strongest when:
Correct : B. The magnetising current is flowing
6. The unit usually used to denote flux density is the:
Correct : A. Gauss
7. Which statement is true when related to magnetic lines of force?
Correct : D. All of the above
8. Magnetic lines of force:
Correct : B. Form a closed loop
9. The areas on a magnetised part from which the magnetic field is leaving or returning
into the part are called:
Correct : C. Magnetic poles
10. The magnetism which remains in a piece of magnetisable material after the
magnetising force has been removed is called the:
Correct : B. Residual field
11. Which technique is the most sensitive?
Correct : A. Continuous
12. The point at which the magnetism in a material cannot be increased even though the
magnetising force continues to increase is known as the:
Correct : B. Saturation point
13. An electric current through a copper wire:
Correct : A. Creates a magnetic field around the wire
14. A longitudinal surface crack in a circularly magnetised part will cause:
Correct : C. A magnetic leakage field
15. The type of current that is best suited to detect surface discontinuities is:
Correct : B. AC
16. Retentivity:
Correct : C. Represents the ability of a material to retain a portion of the magnetic field set up in it after the magnetising force has been removed
17. Demagnetisation:
Correct : A. May be easy or difficult depending on the type of material
18. What rule describes the direction of current flow (+ to -) when lines of magnetic force
surround a conductor?
Correct : B. Right hand rule
19. The proper number of ampere-turns for a given test specimen is determined by:
Correct : D. Its diameter and length
20. An electrical yoke produces:
Correct : A. A longitudinal field
21. In longitudinal magnetisation the proper term for calculating magnetising force is:
Correct : B. Ampere-turns
22. The amount of amperage used for magnetic particle inspection using the prod method
is determined from the:
Correct : B. Distance between the prods
23. Which of the following is the most effective method for the detection of extremely
deep-lying defects:
Correct : D. Dry continuous method using half wave rectified current with prods
24. What method provides greater sensitivity, particularly in locating subsurface
discontinuities?:
Correct : A. Continuous
25. Which type of current has a ‘skin effect’:
Correct : A. AC
26. When using the wet continuous method, the flow of suspension from the hose should
be shut off:
Correct : C. While the current is flowing
27. The area of maximum induced field strength using a yoke is:
Correct : C. The area directly between the poles
28. The strongest magnetic field in a coil is at the:
Correct : B. Inside edge
29. What equipment is used to determine if a part has been demagnetised?
Correct : B. A field meter
30. Which of the following will best define surface cracks?
Correct : C. AC
31. Applying the theory of the ‘Right Hand Rule’, a longitudinal surface defect in a round bar is detected by ‘current passing in a direction parallel to the direction of expected defects’ because:
Correct : B. The magnetic field is at right angles to the defect
32. Why are magnetic particles available in different colours?
Correct : C. For both a and b
33. A magnetic particle build-up from a discontinuity is strongest when the discontinuity
is oriented:
Correct : C. 90o to the magnetic field
34. Why is it preferable to disassemble parts before magnetic particle inspection?
Correct : D. All of the above
35. Fluorescent magnetic particle indications should be inspected under
Correct : C. Black light
36. Why should one avoid using a high velocity flow of a wet testing media over the test
area
Correct : A. It may wash away a fine or lightly held indication
37. What are the three causes of non-relevant indications?
Correct : B. Change of section thickness, very high amperage, drilled hole near surface
38. Magnetic particle inspection is not a reliable method of detecting
Correct : B. Deep seated cavities
39. A defect open to the surface produces an indication which is
Correct : A. Sharp and distinct
40. Wet magnetic bath strength is checked by which of the following
Correct : C. Settling test
41. When preparing a bath it is important to have the bath strength at a proper level, as too many particles can result in:
Correct : C. Masking the indications
42. Magnetic particle is a non-destructive examination method used for:
Correct : C. Both a and b
43. A part is adaptable to magnetic particle inspection if
Correct : B. The material is ferromagnetic
44. The permeability of a material describes:
Correct : A. The ease with which it can be magnetized
45. If a crack exists in a circular magnet, the attraction of magnetic particles to the crack is
caused by:
Correct : B. A leakage field
46. The flux within and surrounding a magnetised part or around a conductor carrying a
current is known as:
Correct : B. Magnetic field
47. A metal that is difficult to magnetise is said to have:
Correct : B. Low permeability
48. Which residual field is most difficult to demagnetise?
Correct : B. Circular
49. Which brings out surface indications most clearly?
Correct : A. AC
50. To detect lengthwise defects on the inside diameter of hollow parts, you should:
Correct : C. Pass current through a central conductor
51. Which of the following is most often used for dry magnetic particle inspection:
Correct : B. Half wave rectified alternating current
52. When a magnetic field is induced in a part with prods spaced 150mm apart, the field
is:
Correct : B. Circular
53. With current flowing from + to - in a coil, a longitudinal field is created. Which of the
following may be used to establish the direction of the magnetic field?
Correct : B. Right hand rule
54. Which form of magnetisation is easiest to control in most parts?
Correct : A. Longitudinal magnetisation
55. The strength of a magnetic field within a coil is determined by:
Correct : D. All of the above factors
56. The field in a section of pipe being magnetised by means of a central conductor is
stronger at:
Correct : C. The inside surface of the pipe
57. The space within and surrounding a magnetized part of a conductor carrying a current
is known as:
Correct : B. Magnetic field
58. Subjecting the part to a magnetic field that is constantly reversing in polarity and
gradually diminishing in strength accomplishes which of the following:
Correct : B. Removes residual field from the part
59. The type of method most frequently used with mobile equipment is the:
Correct : D. Dry magnetic particle powder method
60. Which of the following is NOT a liquid vehicle in which particles are suspended in
magnetic particle testing:
Correct : C. Gasoline
61. The most common cause of non relevant indications in MT is:
Correct : A. Over magnetisation
62. When a ferromagnetic material is in an unmagnetized state, the domains are:
Correct : C. Randomly organized
63. Paramagnetic materials:
Correct : B. Are affected by magnetic fields
64. What type of magnetization uses the formula: I = 45000/(L/D)N where I is the current in Amperes, N the number of turns of the magnetizing coil, L the length of the cylindrical test piece and D its diameter.
Correct : B. Longitudinal
65. The magnetic field is the strongest when:
Correct : A. The magnetising current is flowing
66. The retentivity of a material describes:
Correct : C. The ability to retain the magnetic field
67. A material with a wider hysteresis loop has:
Correct : C. Higher residual magnetism
68. The unit usually used to denote flux density is the:
Correct : C. Gauss
69. Which technique is the most sensitive?
Correct : B. Continuous
70. What rule describes the direction of current flow (+ to -) when lines of magnetic force
surround a conductor?
Correct : B. Right hand rule
71. The opposition that a ferromagnetic material shows to the establishment of a magnetic
field is called:
Correct : B. Reluctance
72. The magnetism which remains in a piece of magnetisable material after the magnetising force has been removed is called the:
Correct : B. Residual field
73. A material with a narrower hysteresis loop has:
Correct : D. All of the above
74. The correct number of ampere-turns for a given test specimen is determined by:
Correct : D. Its diameter and length
75. Which of the following is not a property of magnetic lines of force?
Correct : B. The density increases with distance from the poles of a permanent magnet
76. Surrounding an electromagnet, the magnetic field is strongest:
Correct : D. Just prior to current reversal
77. The value of permeability is:
Correct : A. A fixed value depending upon the type of material
78. The flux density of the magnetism induced by a coil is affected by:
Correct : D. All of the above
79. How many turns of a coil will be needed to establish a longitudinal field in a steel shaft that is 22.86 cm (9 inches) long and 7.62 cm (3 inches) in diameter? 3000 amperes magnetizing current is available, it is desired to magnetize the part in accordance with the formula NI = 45,000/(L/D):
Correct : C. 5
80. How many ampere-turns are required to magnetize a part that is 40.6 cm (16 inches)
long and 5 cm (2 inches) in diameter?
Correct : B. 5625 ampere-turns
81. The lines of flux or force in a circularly magnetized ferromagnetic bar:
Correct : D. Are contained within and around the part
82. In which magnetizing method is the current passed directly through the part, thereby
setting up a magnetic field at right angles to the current flow?
Correct : D. None of the above
83. Which of the following is false concerning a magnetic field in and around a hollow conductor as compared to that of a solid conductor of the same outside diameter when both are of the same magnetic material, and when the applied current is the same?
Correct : C. The fields outside the conductors are the same
84. The field in a section of ferromagnetic pipe being magnetized by means of a central
conductor is strongest at the:
Correct : C. Inner surface of the pipe
85. For a 7.6 cm (3 inches) diameter bar how much current is needed to magnetize the bar
for the detection of longitudinal discontinuities:
Correct : D. 3000 amperes
86. For detection of longitudinal discontinuities a 7.6 cm (3 inches) diameter bar is
magnetized in:
Correct : B. The circular direction
87. A bar that is 5 cm (2 inches) by 10 cm (4 inches) by 30.5 cm (12 inches) is being magnetized in the circular direction. About how many amperes are required using the perimeter approach?
Correct : C. 3800
88. An advantage of AC is that:
Correct : D. All of the above
89. When a magnetic field cuts across a crack:
Correct : C. Magnetic poles form at the edges of the crack
90. A disadvantage of AC current is that it:
Correct : B. Has poor penetrating power
91. What causes a leakage field in a steel bar?
Correct : A. A crack
92. An indication is a defect under which of the following conditions?
Correct : B. If it exceeds the limits of a standard or specification
93. Paint will not affect the detection of a crack if:
Correct : C. The crack is sharp and the paint is thin
94. A magnetic particle indication is sharp and very fine; this suggests that the
discontinuity is:
Correct : B. A shallow, tight surface crack
95. Among the following, the best type of current for the detection of fatigue cracks is:
Correct : B. Alternating current
96. Continuous magnetization provides the most sensitivity because:
Correct : C. All of the above
97. The sensitivity of magnetic particle testing is greatest when the discontinuity is:
Correct : C. Perpendicular to the direction of the magnetic flux
98. To provide reliability and reproducibility in magnetic particle testing, written
procedures should include:
Correct : D. All of the above
99. The magnetic particles are noticed to bunch in some fillet areas and stand on end on
the edge of a part being magnetized. These observations indicate that the:
Correct : B. Flux density is excessive
100. Flux density is a measure of the number of magnetic flux lines perpendicular to an area of cross-section. If a discontinuity is in the plane of the unit area, the strongest magnetic article indication will be formed when the discontinuity is: