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Description
Flashcards by Gamaliel Walker, updated more than 1 year ago
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Created by Gamaliel Walker
about 8 years ago
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| Question | Answer |
| 1. Which of the following is not a basic component of an eddy current test system? a. Amplifier. b. Sine wave generator. c. Wear-resistant tape. d. Filter. | c. Wear-resistant tape. |
| 2. When conducting an eddy current test using a differential comparison coil arrangement that compares an external reference standard with the test specimen, the system should be nulled or balanced: a. with only the reference standard in one coil. b. with the reference standard in one coil an acceptable test specimen in the other coil. c. with the reference standard in one coil and an unacceptable test specimen in the other coil. d. with only the the test specimen in one coil. | b. with the reference standard in one coil and an acceptable test specimen in the other coil. |
| 3. The impedance of a test coil will increase if the: A. test frequency increases. B. inductive reactance of the coil decreases. C. inductance of the coil decreases. D. resistance of the coil decreases. | A. test frequency increases. |
| 4. When a metal part is placed in an Eddy current test coil, the impedance of the coil will be changed by all of the following properties of the part except: A. conductivity. B. dimensions. C. permeability D. nonconductive coating. | D. nonconductive coating. |
| 5. An Eddy current test makes use of electrical induced in a conductive article by: A. gamma rays. B. an altrrnating magnetic field. C. a piezoelectric force. D. a decay process. | B. an altrrnating magnetic field. |
| 6. The conductivity of a material can be altered by changing the: A. amount of paint on the part surface. B. chemistry of the part. C. length of the part. D. volume of the part. | C. chemistry of the part |
| 7. When testing plate with a probe coil, it is noted that the eddy current output indication varies as the distance from the coil to the surface of the test part varies. The term used to describe this action is: A. fill factor. B. liftoff. C. phase differentiation. D. edge effect. | B. liftoff |
| 8. Liftoff is utilized in: A. measuring permeability changes. B. measuring conductivity changes. C. measuring the thickness of nonconductive coating. D. determining proper test frequency. | C. measuring the thickness of nonconductive coating. |
| 9. When inspecting products with a uniform cross section, an Eddy current signal is produced when the leading end or trailing end of the product approaches the test coil. This phenomenon is referred to as: A. liftoff. B. end effect. C. fill effect. D. phase discrimination. | B. end effect. |
| 10. Which of the following conditions would be the most difficult to detect when eddy current testing a rod with an encircling coil? A. A deep surface crack that has a depth of 30% of the rod diameter. B. A small inclusion in the center of the rod. C. A 5% change in a diameter. D. A 10% change in conductivity. | B. A small inclusion in the center of the rod. |
| 11. Which of the following test frequencies would produce eddy currents with the largest depth of penetration? A. 100 Hz B. 10 kHz C. 1 MHz D. 10 MHz | A. 100 Hz |
| 12. A test coil's opposition to the flow of alternating current, causing the current to lag the voltage, is called: A. resistance. B. inductive reactance. C. impedance. D. capacitive reactance. | B. inductive reactance. |
| 13. An increase in the impedance of a test coil will: A. produce an increase in the voltage through the test coil. B. cause a decrease in the measured voltage across the test coil C. not affect the voltage in the test coil. D. decrease the voltage applied to the coil | A. produce an increase in the voltage through the test coil. |
| 14. Which of the following will not affect the inductance of a test probe? A. Test frequency. B. Number of turns of wire in the coil. C. Coil width. D. Coil cross- section area. | A. Test Frequency. |
| 15. Small-diameter probe coils would typically be used for the detection of: A. slow changes in dimensions. B. gradual changes in conductivity. C. variations in heat treatment. D. small surface discontinuities. | D. small surface discontinuities. |
| 16. Which of the following expresses the primary purpose(s) of the secondary winding(s) in an Eddy current probe? A. Induce eddy current in the test specimen. B. Detect changes in the eddy current flow. C. Induce eddy currents in the test specimen and detect changes in the eddy current flow. D. Provide DC saturation. | B. Detect changes in the eddy current flow. |
| 17. Which of the following eddy current test coil arrangements use one area of the test specimen as a reference standard against which another area on the same specimen is simultaneously compared? A. Single absolute coil B. Double absolute coil. C. DC saturation coil. D. Differential coil. | D. Differential coil. |
| 18. Reference standards used for electromagnetic testing: A. must contain artificial discontinuities such as notches you conducted. B. must contain natural discontinuities such as cracks and inclusions. C. must be free of measurable discontinuities. D. may contain artificial or natural discontinuities or be free of discontinuities depending on the test system and the type of test being conducted. | D. may contain artificial or natural discontinuities or be free of discontinuities depending on the test system and the type of test being conducted. |
| 19. A tool used to ensure that the test system does not drift during a test cycle is called a: A. DGS standard B. calibration standard. C. mix algorithm. D probe. | B. calibration standard. |
| 20. Which of the following could not be tested by the electromagnetic testing method? a. a 102 mm (4 in.) thick plate to be tested for small discontinuities throughout the plate. B. tubing to be tested for surface cracks. c. rod to be tested for laps and seams. D. tubing to be tested for variations in outside diameter. | a. a 102 mm (4 in.) thick plate to be tested for small discontinuities throughout the plate. |
| 21. Which of the following is not true about an eddy current test? a. it can be used for high-speed testing. B. it can accurately measure conductivity. c. it can be set up to provide high sensitivity to small discontinuities. D. it can penetrate up too 152 mm(6 in.) in a test part. | D. it can penetrate up too 152 mm(6 in.) in a test part. |
| 22. the entire circumference of a tube can be evaluated at one time when using. a. an encircling coil. B. a bobbing coil. c. a pencil probe. D. a pancake coil. | a. an encircling coil. |
| 23. it is often possible to sort various nonferromagnetic alloys of a metal by means of an eddy current test when: a. there is a unique range of permeability values for each alloy. B. there is a unique range of conductivity values for each alloy. c. the direction of induced eddy currents varies for each alloy. D. the magnetic domains for each alloy are different. | B. there is a unique range of conductivity values for each alloy. |
| 24. which of the following products would be most applicable to a test using an inside coil? a. sheet. B. rod. c. bolt hole. D. coating thickness. | c. bolt hole. |
| 25. when eddy current testing a rod for discontinuities, which of the following would not be considered a source of noise? a. improper adjustment of the hold-down rollers used to center the rod in the coil B. feeding rod through the coil at an excessive speed. c. pits. D. tubing end responses. | c. pits. |
| 26. one method of reducing nonrelevant indications when eddy current testing ferromagnetic materials is to: a. decrease the pressure on the hold-down rollers B. use a direct current saturation coil to magnetically saturate the test specimen. c. readjust the gain control. D.increase the rate of feedthrough in the coil | B. use a direct current saturation coil to magnetically saturate the test specimen. |
| 27. in order to generate measurable eddy current in a test specimen, the specimen must be: a. a conductor. B. an insulator. c. either a conductor or an insulator. D. a ferromagnetic material. | a. a conductor. |
| 28. which of the following is not a readout system used in to present eddy current test information? a. alarms B. litmus paper c. cathode ray tube D. digital data storage. | B. litmus paper |
| 29. which of the following statements best describe the selection of eddy current test frequency? a. the frequency must equal the flfc ratio to give an accurate test B. the frequency must be within +/- 3% of the flfc ratio to give an accurate test c. there is a range of suitable frequencies centered around the optimum frequency. D. the frequency should be within +/- 25% of the characteristic frequency. | c. there is a range of suitable frequencies centered around the optimum frequency. |
| 30. which of the following options would not have the potential to improve the displayed signal-to-noise ratio of a test? a. change to a test frequency that will decrease the noise. B. increase the amplification of the test instrument c. improve the fill factor D. enable filter functions in the instrument. | B. increase the amplification of the test instrument |
| 31. a coil's magnetic field may be viewed as a distribution of lines of flux around the coil. the number of lines per unit is defined as: a. magnetic probability B. flux density c. magnetic coupling D. hysteria density. | B. flux density |
| 32. eddy current test techniques are best suited to: a. measure nonconductive coating thickness on conductive materials. B. define the crystalline structure of a material. c. define the chemistry of an alloy D. test for delamination in carbon fiber structures. | a. measure nonconductive coating thickness on conductive materials. |
| 33. eddy current cannot be induced in: a. latex paint B. aluminum c. steel D. copper. | a. latex paint |
| 34. eddy current always travel: a. in a circular path. B. in nonconductive materials c. radially when testing rod with an encircling coil. D. in a gas. | a. in a circular path. |
| 35. a term used to define a standardized condition in a device or system which results in zero output is: a. high- frequency standardization. B. integration. c. null or balance. D. differentiation | c. null or balance. |
| 36. a term used to describe holes, groves, notches, etc., that are introduced into a reference standard to provide accurately reproducible quality levels is: a. a natural discontinuity. B. an artificial discontinuity. c. an ellipse. D. damage mechanism identifiers. | B. an artificial discontinuity. |
| 37. a term used to define one or more turns or loops of a conductor wound in such a manner as to produce an axial magnetic field when current passes through the conductor is: a. coil. B. a resistor c. a capacitor D. an oscillator | a. coil. |
| 38. Which of the following is not a common application for eddy current testing? a. measuring of conductivity B. measuring of the thickness of thin metal sections c. detection of surface and subsurface discontinuities. D. detection of lack of bonding between conductive and nonconductive material. | D. detection of lack of bonding between conductive and nonconductive material. |
| 39. Which of the following is not a primary for using an eddy current standard? a. to determine if the eddy current test system is capable of performing the test properly. B. to determine if a discontinuity is a cause for rejection. c. to determine the instrument control settings needed to pass the highest percentage of test specimens run. D. to determine if the sensitivity of a test system has drifted with time. | c. to determine the instrument control settings needed to pass the highest percentage of test specimens run. |
| 40. When you determine that a discontinuity detection instrument has been set up incorrectly, or is defective, all material: a. should be retested since the time that a correct setup or proper operation was last verified. B. accepted should be retested. c. rejected should be retested. D. inspected should be scrapped. up | a. should be retested since the time that a correct setup or proper operation was last verified. |
| 41. An Eddy current system will effectively measure variations in conductivity caused by: a. size of the material. B. geometric shape of the material. c. the process used to cast or form the material. D. hardness of the materials as a result of the heat treatment. | D. hardness of the materials as a result of the heat treatment. |
| 42. A length of tubing containing a notch of uniform width and depth running from end to end, when tested with an encircling self-reference differential coil system, will produce: a. erratic signals. B. a discontinous signal. c. no signal change. D. excessive signals. | c. no signal change. |
| 43. An encircling coil is generally used to inspect a test object for: a. discontinuities with a circumferential orientation. B. deep subsurface discontinuities c. discontinuities on the inside surface. D. discontinuities on the outside surface. | D. discontinuities on the outside surface. |
| 44. One principal advantage of spinning-probe eddy current testing is: a. the ability to locate the exact position of discontinuities. B. it's relative insensitivity to permeability variations. c. increase production rates D. decrease sensitivity to edge effect or end effect. | a. the ability to locate the exact position of discontinuities. |
| 45. A spinning probe eddy current instrument would be most useful in: a. measuring the hardness of ferromagnetic steel products. B. discontinuities detection in hexagonal material. c. detecting and precisely locating surface discontinuities. d. inspection of copper bus bars for electrical conductivity. | c. detecting and precisely locating surface discontinuities. |
| 46. What causes phase shift in an Eddy current test coil? a. a change in the ratio of inductive reactance (XL) to resistance(R). B. a change in the sensitivity setting of the instrument. c. use of modulation analysis. D. measure the test frequency. | a. a change in the ratio of inductive reactance (XL) to resistance(R). |
| 47. in an electromagnetic test system, the test frequency is controlled by the: a. oscilloscope B. sensitivity setting c. oscillator circuit D. modulation analysis setting. | c. oscillator circuit |
| 48. Variations in the chemical composition of a nonferromagnetic alloy would most likely affect its: a. permeability B. conductivity c. diameter D. frequency. | B. conductivity |
| 49. Which of the following frequencies will provide the greatest eddy current penetration in aluminum? a. 1 kHz B. 10 kHz c. 3 kHz D. 300 Hz | D. 300 Hz |
| 50. A symbol commonly used to express conductivity is: a. u B. O c. XL D. R | B. O |
| 51. A symbol commonly used to express permeability is: a. u B. O c. XL D. R | a. u |
| 52. The method used to generate eddy current in a test specimen by means of a coil can most closely be compared with the action of a: a. transformer B. capacitor c. storage battery D. generator | a. transformer |
| 53. When eddy current is used to test a nonferrous specimen, a discontinuity will: a. increase the effect conductivity of the specimen. B. increase the effective permeability of the specimen. c. decrease the effective conductivity of the specimen. D. cause a decrease in measured voltage across the coil. | c. decrease the effective conductivity of the specimen. |
| 54. Self-comparison differential channels would be best for the detection of: a. long tapered discontinuities B. short abrupt discontinuities. c. temperature differences D. slow-changing tube wall thickness. | B. short abrupt discontinuities. |
| 55. The fill factor is a ratio that is: a. identical to the liftoff of a surface coil. B. always greater than one (1). c. ideally 3:1. D. always less than one (1), or 100%. | D. always less than one (1), or 100%. |
| 56. A secondary magnetic field produced by eddy current induced in a nonmagnetic conductor close to the inducing coils: a. induces a magnetic field parallel to the surface. b. aids the coil's magnetic field. c. opposes the coil's magnetic field. D. decreases the frequency of the current. | c. opposes the coil's magnetic field. |
| 57. The process of comparing the reading or output of an instrument, device, or dial with a standard to determine the instrument's accuracy, capacity, or graduations is referred to as: a. calibration. B. differentiation. c. integration. d. phase shifting. | a. calibration. |
| 58.Ferromagnetic materials that have been magnetically saturated to suppress permeability variations may retain a certain amount of the magnetization. This is called: a. coercive force. B. residual magnetism. c. hystersis loop. D. hystersis loss. | B. residual magnetism. |
| 59. Which of the following is determined by the length of wire used to wind a coil? a. specific resistance B. Resistance c. Frequency of the applied AC current. D. Voltage of the applied AC current. | B. Resistance |
| 60. The depth of penetration would _____ if the localized permeability of a material increased. a. increase B. decrease c. remain constant D. increase the conductivity | B. decrease |
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