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Mag Particle LVL1
| Question | Answer |
|---|---|
| 1. “Magnetic particle” is a nondestructive examination method used for: a. locating surface discontinuities b. locating near surface discontinuities c. both a and b d. detecting material separation | c. both a and b |
| 2. Ferromagnetic material is: a. strongly attracted by a magnet b. capable of being magnetized c. both a and b d. not capable of being magnetized | c. both a and b |
| 3. The permeability of a material describes the: a. ease with which it can be magnetized b. depth of the magnetic field in the part c. length of time required to demagnetize it d. ability to retain the magnetic field | a. ease with which it can be magnetized |
| 4. The retentivity of a material describes the: a. ease with which it can be magnetized b. depth of the magnetic field in the part c. length of time required to demagnetize it d. ability to retain the magnetic field | d. ability to retain the magnetic field |
| 5. Why are magnetic particles available in different colors? a. for color contrast with the part surface b. to enhance the detection of indications c. both a and b d. different colors are used with different magnetic flux values | c. both a and b |
| 6. Which of the following can be magnetized? a. iron b. nickel c. cobalt d. all of the above | d. all of the above |
| 7. The magnetic field is strongest when the: a. magnetizing voltage is flowing b. magnetizing current is flowing c. material exhibits high coercive forces d. magnetizing current is not flowing | b. magnetizing current is flowing |
| 8. If a crack exists in a circular magnet, the attraction of magnetic particles to the crack is caused by a: a. coercive force b. leakage field c. Doppler effect d. high reluctance at the crack | b. leakage field |
| 9. The unit usually used to denote flux density is the: a. Gauss b. Henry c. farad d. ampere | a. Gauss |
| 10. Which statement is true when related to magnetic lines of force? a. they never cross b. they are most dense at the poles of a magnet c. they seek the path of least resistance d. all of the above | d. all of the above |
| 11. Magnetic flux lines which are parallel to a discontinuity produce: a. strong indications b. weak indications c. no indications d. fuzzy indications | c. no indications |
| 12. A part is adaptable to magnetic particle inspection if: a. it is attached to an electrostatic field b. the material is ferromagnetic c. the material is nonferrous d. the material is an electric conductor | b. the material is ferromagnetic |
| 13. What rule describes the direction of current flow (+ to —) when lines of magnetic force surround a conductor? a. the left hand rule b. the right hand rule c. the flux rule d. the reluctance rule | b. the right hand rule |
| 14. The magnitude of the residual magnetic field in a specimen is dependent on the: a. L/D ratio (length to diameter) b. strength of the applied magnetizing force c. right hand rule d. left hand rule | b. strength of the applied magnetizing force |
| 15. The proper number of ampere-turns for a given test specimen is determined by: a. its length b. the material c. both a and b d. it's diameter | c. both a and b |
| 16. A circular field may be induced into a specimen by: a. direct induction (head shot) b. direct induction (prods) c. central conductor d. all of the above | d. all of the above |
| 17. An electrical yoke produces: a. a longitudinal field b. a circular field c. alternating fields d. a swinging field | a. a longitudinal field |
| 18. a coil around the part produces: a. a circular field b. a longitudinal field c. either a or b depending on the type of current applied d. an intermittent field | b. a longitudinal field |
| 19. In longitudinal magnetization, the proper term for calculating magnetizing force is: a. amperes b. ampere-turns c. watts d. ohms | b. ampere-turns |
| 20. Magnetic lines of force: a. travel in straight lines b. form a closed loop c. are randomly oriented d. overlay in highly ferromagnetic materials | b. form a closed loop |
| 21. A magnetic particle build-up from a discontinuity is strongest when the discontinuity is oriented: a. 180° to the magnetic field b. 45° to the magnetic field c. 90° to the magnetic field d. 90° to the current flow | c. 90° to the magnetic field |
| 22. A specimen may be demagnetized by: a. heat treatment above Curie temperature b. an AC coil c. reversing DC fields d. all of the above | d. all of the above |
| 23. Advantage of MT testing over penetrant testing? a. it can detect surface discontinuities with foreign material embedded in them b. it is faster on individual parts c. it can detect near-surface discontinuities d. all of the above | d. all of the above |
| 24. The amount of amperage used for magnetic particle inspection using the prod method is determined from the: a. type of material b. distance between the prods c. diameter of the part d. total length of the part | b. distance between the prods |
| 25. The flux within and surrounding a magnetized part or around a conductor carrying a current is known as: a. saturation point b. magnetic field c. ferromagnetic d. paramagnetic | b. magnetic field |
| 26. The areas on a magnetized part from which the magnetic field is leaving or returning into the part are called: a. salient points b. defects c. magnetic poles d. nodes | c. magnetic poles |
| 27. A metal that is difficult to magnetize is said to have: a. ‘high permeability b. low permeability c. high reluctance d. low retentivity | b. low permeability |
| 28. The magnetism that remains in a piece of magnetizable material after the magnetizing force has been removed is called the: a. tramp field b. residual field c. damped field d. permanent field | b. residual field |
| 29. Why disassemble parts before magnetic particle inspection? a. disassembly makes all surface areas visible b. interfaces create leakage fields which exam c. it is easier to handle disassembled parts d. all of the above | d. all of the above |
| 30. Subsurface discontinuity indications usually appear: a. sharp and distinct b. sharp and wide c. wide and fuzzy d. high and loosely held | c. wide and fuzzy |
| 31. Which residual field is most difficult to demagnetize? a. longitudinal b. circular c. vector d. binodal | b. circular |
| 32. Which technique is the most sensitive? a. continuous b. residual c. interrupted d. counter-current | a. continuous |
| 33. Which type of current brings out surface indications most clearly? a. AC b. DC c. pulsed DC d. DC with surge | a. AC |
| 34. Fluorescent magnetic particle indications should be inspected under: a. fluorescent light b. any light c. black light d. neon light | c. black light |
| 35. Inspecting a part by magnetizing, removing the current flow, and then applying the medium is called the: a. continuous method b. wet method c. residual method d. dry method | c. residual method |
| 36. False indications are caused by magnetic particles being held to the part by which of the following means? a. gravity b. mechanical c. both a and b d. none of the above | d. none of the above |
| 37. Most effective method to detect extremely deep lying defects? a. dry residual method using DC with surge b. wet continuous method using half-wave rectified current c. wet residual method d. dry continuous method using prods with HWRC | d. dry continuous method using prods with HWRC |
| 38. A curve to show magnetizing force to the strength of the magnetic field produced in a certain material. It is known as the: a. magnetic force curve b. hysteresis curve c. saturation curve d. induction curve | b. hysteresis curve |
| 39. What method provides greater sensitivity, particularly in locating subsurface discontinuities? a. continuous b. residual c. circular d. longitudinal | a. continuous |
| 40. If examining weld, 1st current-750 Amps 2nd -400 amps, which is true? a. check if demag needed between exams b. no precautions needed between exams c. this is not a valid technique d. there is no need to examine a weld in two directions | a. check if demag needed between exams |
| 41. When there is absolutely no pattern or distribution of magnetic particles, the possible cause is that: a. the material is nonmagnetic b. the amperage setting is too low c. no current is being applied d. any of the above could be true | d. any of the above could be true |
| 42. What are the three causes of nonrelevant indications? a. lack of fusion, change of section , grinding cracks b. change of section , high amperage, hole drilled near surface c. high amperage, hole drilled near surface, blow holes d. drilled | b. change of section , high amperage, hole drilled near surface |
| 43. Do not allow residual MT parts laid on a rack b/4 applying of MT particles to rub or touch because? a. there is a possible loss of the magnetic field b. it may cause magnetic writing c. it may damage the part d. it makes parts hard to handle | b. it may cause magnetic writing |
| 44. The point at which the magnetism in a material cannot be increased even though the magnetizing force continues to increase is known as the: a. salient pole b. saturation point c. residual point d. remnant point | b. saturation point |
| 45. Which type of current has a "skin effect"? a. AC b. DC c. half-wave rectified d. full-wave rectified | a. AC |
| 46. A high velocity flow of wet method bath over specimen surfaces after removal MT current may cause: a. a fine or weakly held indication to be washed away b. no problems c. particles to be splashed into eyes d. none of the above | a. a fine or weakly held indication to be washed away |
| 47. Residual magnetic particle inspection may be used when: a. parts are irregular in shape b. parts are highly retentive c. parts are highly stressed d. evaluating continuous method indications | b. parts are highly retentive |
| 48. Magnetic particle inspection is a reliable method for detecting all of the following indications except: a. laps b. deep seated cavities c. cracks d. seams | b. deep seated cavities |
| 49. The wet fluorescent magnetic particle inspection method is the same as the standard wet magnetic particle method with the exception of requirements for: a. black light b. higher current c. a different machine d. type of current | a. black light |
| 50. A defect open to the surface produces an indication that is: a. sharp and distinct b. wide and indefinite c. criss-cross d. high and fuzzy | a. sharp and distinct |
| 51. Which of the following will produce circular magnetism? a. passing current through a coil b. placing the test part in a solenoid c. passing current through prods d. yokes | c.passing current through prods |
| 52. For wet continuous method, the flow of suspension from the hose should be shut off: a. immediately after applying the current b. immediately before applying the current c. while the current is flowing d. 30 seconds before applying the current | c. while the current is flowing |
| 53. The strongest magnetic field in a coil is at the: a. outside edge b. inside edge c. center d. end | b. inside edge |
| 54. To detect lengthwise defects on the inside diameter of a hollow part, you should: a. pass current through it b. magnetize it with a coil c. pass current through a central conductor d. increase the amperage used | c. pass current through a central conductor |
| 55. What equipment is used to determine whether a part has been demagnetized? a. a magnet on the part b. a field meter c. a survey meter d. careful observation for clinging magnetic particles | b. a field meter |
| 56. Which of the following is most often used for dry magnetic particle inspection? a. full cycle direct current b. half-wave rectified alternating current c. high voltage, low amperage current d. direct current from electrolytic cells | b. half-wave rectified alternating current |
| 57. An electric current through a copper wire: a. creates a magnetic field around the wire b. creates magnetic poles in the wire c. magnetizes the wire d. does. not create a magnetic field | a. creates a magnetic field around the wire |
| 58. Why should parts be cleaned after demagnetization? a. to assure that the magnetic particles are removed b. to prevent false indications c. tn save the solids of the suspension d. to prevent cracking during heat treatment | a. to assure that the magnetic particles are removed |
| 59. In circular magnetization, the magnetizing force is expressed in amperes. What term is used to express the magnetizing force in longitudinal magnetization? a. amperes b. ampere-turns c. consequent poles d. volts | b. ampere-turns |
| 60. A longitudinal surface crack in a circularly magnetized part will cause: a. the magnetic field to die out b. a decrease in permeability c. a magnetic leakage field d. a current to flow | c. a magnetic leakage field |
| 61. In a magnetic particle test, assuming that all of the following are in the same relative position in a small part, which would be the hardest to detect? a. a surface crack b. a near surface crack c. a scratch d. a seam | c. a scratch |
| 62. If wet magnetic particle suspension is not uniform, then: a. indication strength may vary, creating erroneous interpretation. b. the magnetic flux would not be uniform c. greater mobility would be required d. the part cannot be magnetized | a. indication strength may vary, creating erroneous interpretation. |
| 63. Which of the following will best define surface cracks? a. half-wave rectified AC b. DC c. AC d. surge current | c. AC |
| 64. When a magnetic field is induced in a part with prods 70. spaced 152 mm (6 in.) apart, the field is: a. solenoidal b. circular c. longitudinal d. distorted trapezoidal | b. circular |
| 65. Using “Right Hand Rule,” passing current parallel to expected defects in round bar reveals: a. current direction is in line with the defect b. MT field is at right angles to defect c. it makes no difference d. MT field is parallel to the defect | b. MT field is at right angles to defect |
| 66. If a current is passed through an electrical conductor, what will surround the conductor? a. an eddy current field b. current c. a magnetic field d. a residual field | c. a magnetic field |
| 67. With coil current flowing from + to —, a longitudinal field is created. Which of the following may be used to establish the direction of the magnetic field? a. the left hand rule b. the right hand rule c. Ohm’s law d. there is no relevant law | b. the right hand rule |
| 68. When ferromag material is placed into a coil, the magnetic lines concentrate themselves in the material and: a. create a longitudinal magnetic field b. create a circular magnetic field c. create a longitudinal-circular field d. have no effect | a. create a longitudinal magnetic field |
| 69. Which form of magnetization is easiest to control in most parts? a. longitudinal magnetization b. permanent magnetism c. circular magnetization d. parallel magnetization | c. circular magnetization |
| 70. When inspecting a tabular product for surface defects along its length, the best type of magnetic field to use is a: a. longitudinal field b. circular field c. swinging field d. yoke magnetization | b. circular field |
| 71. The area of maximum induced field strength using a yoke is: a. at the North pole of the yoke b. at the South pole of the yoke c. the area directly between the poles d. on the outside of pole pieces | c. the area directly between the poles |
| 72. The strength of the magnetic field induced in a part is often referred to as: a. current density b. voltage c. flux density d. retentivity | c. flux density |
| 73. The major factor that determines the success of magnetic particle inspection is the: a. field strength b. voltage on magnetizing coil c. current through the coil d. time of magnetization | a. field strength |
| 74. The type of current that is best suited to detect surface discontinuities is: a. DC b. AC c. pulsating DC d. half-wave | b. AC |
| 75. When preparing MT bath, it is important to have the proper concentration bath strength as excess particles can result in: a. lowering test amperage b. need to increase the magnetizing current c. the masking of indications d. none of the above | c. the masking of indications |
| 76. One advantage of using fluorescent particles is a. that less equipment is required b. the high speed of inspection c. the cost d. that they are more readily attracted | b. the high speed of inspection |
| 77. The proper way to apply dry magnetic particle powder is to: a. forcibly apply it with air b. roll the material in the container of powder c. apply it from the bottom of the part d. float the particles to exam surface as gently as possible | d. float the particles to exam surface as gently as possible |
| 78. When using the wet particles in water suspension, wetting agents are added to: a. prevent freezing b. prevent corrosion of inspection equipment c. ensure the proper wetting of the part d. decrease the amount of water needed | c. ensure the proper wetting of the part |
| 79. When preparing an inspection bath, the amount of magnetic particles per gallon of fluid is called its: a. measuring scale b. particle number c. strength or concentration d. usable limits | c. strength or concentration |
| 80. Coercive force: a. describes how MT particles are suspended liquid when using wet MT b. describes how MT force used with the continuous method c. represents the reverse MT force used to remove the residual magnetism d. term not used in MT | c. represents the reverse MT force used to remove the residual magnetism |
| 81. Demagnetization: a. may be accomplished by heating a material above its Curie point b. is always necessary c. can be performed only with AC d. can be performed only with DC | a. may be accomplished by heating a material above its Curie point |
| 82. Retentivity: a. ability to induce magnetism in a ferromag part b. ability of material to resist creating MT flux within it c. is ability of material to retain a portion of the MT field created after MT force removed d. term not used in MT | c. is ability of material to retain a portion of the MT field created after MT force removed |
| 83. Resistance to demagnetization is: a. greater in hard materials than soft materials b. greater in soft materials than hard materials c. the same for both hard and soft materials d. nonexistent | a. greater in hard materials than soft materials |
| 84. Demagnetization: a. may be easy or difficult depending on the type of material b. is easy for materials having a high coercive force c. is always most difficult in materials retaining a high residual field d. all of the above | a. may be easy or difficult depending on the type of material |
| 85. The strength of the wet suspension should be maintained at a given level because: a. a low level might give a weak indication b. a high level may give a heavy background c. both a and b d. none of the above | c. both a and b |
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