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Question 1

1. Low-voltage X-ray tubes are generally fitted with windows made of:
   a. plastic.
   b. beryllium.
   c. glass.
   d. lead.

Answer 1

b. beryllium.

Question 2

2. The projected area of the target of an X-ray tube is called the:
   a. focal spot.
   b. focus.
   c. effective focal spot.
   d. geometric unsharpness.

Answer 2

c. effective focal spot.

Question 3

3. The general method of producing X-rays involves the sudden deceleration of high-velocity electrons in a solid body called a:
   a. focus cup.
   b. filament.
   c. target.
   d. cathode.

Answer 3

c. target.

Question 4

4. If it were necessary to radiograph a 7 in. (177.8 mm) thick steel product, which of the following gamma-ray sources would most likely be used?
   a. Co-60
   b. Tm-170
   c. Ir-192
   d. Cs-137

Answer 4

a. Co-60

Question 5

5. A Co-60 gamma-ray source has an approximate practical thickness limit of:
   a. 2.5 in. (63.5 mm) of steel or its equivalent.
   b. 4 in. (101.6 mm) of steel or its equivalent.
   c. 8 in. (203.2 mm) of steel or its equivalent.
   d. 11 in. (279.4 mm) of steel or its equivalent.

Answer 5

c. 8 in. (203.2 mm) of steel or its equivalent.

Question 6

6. The absorption of gamma rays from a given source when passing through matter depends on:
   a. the atomic number, density, and thickness of the matter.
   b. Young’s modulus value of the matter.
   c. Poisson’s ratio value of the matter.
   d. the specific activity value of the source.

Answer 6

a. the atomic number, density, and thickness of the matter.

Question 7

7. The fact that gases, when bombarded by radiation, ionize and become electrically conductive makes them useful in:
   a. X-ray transformers.
   b. X-ray tubes.
   c. masks.
   d. radiation detection equipment.

Answer 7

d. radiation detection equipment.

Question 8

8. The velocity of electrons striking the target in an X-ray tube is a function of the:
   a. atomic number of the cathode material.
   b. atomic number of the filament material.
   c. voltage difference between the cathode and anode.
   d. current flow in the rectifier circuit.

Answer 8

c. voltage difference between the cathode and anode.

Question 9

9. The uneven distribution of developed grains within the emulsion of a processed X-ray film causes the subjective impression of:
   a. graininess.
   b. streaks.
   c. spots.
   d. white scum.

Answer 9

a. graininess.

Question 10

10. Co-60 is reported to have a half-life of 5.3 years. By how much should exposure time be increased (over that used initially to produce excellent radiographs when the Co-60 source was new) when the source is 2 years old?
    a. No change in exposure time is needed.
    b. Exposure time should be about 11% longer.
    c. Exposure time should be about 37% longer.
    d. Exposure time should be about 62% to 100% longer.

Answer 10

c. Exposure time should be about 37% longer.

Question 11

11. A source of Ir-192, whose half-life is 75 days, provides an optimum exposure of a given test object today in a period of 20 min. Five months from now, what exposure time would be required for the same radiographic density, under similar exposure conditions?
    a. 10 min
    b. 20 min
    c. 1 h and 20 min
    d. 20 min

Answer 11

c. 1 h and 20 min

Question 12

12. Of the following, the source providing the most penetrating radiation is:
    a. Co-60.
    b. 220 kVp X-ray tube.
    c. 15 MeV X-ray betatron.
    d. electrons from Ir-192.

Answer 12

c. 15 MeV X-ray betatron.

Question 13

13. The gamma ray intensity at 1 ft (300 mm) from a 1 Ci (37 GBq) source of radioactive Co-60 is nearest to:
    a. 15 R per hour (150 mSv per hour).
    b. 1000 R per hour (10 000 mSv per hour).
    c. 1 R per min (10 mSv per min).
    d. 10 mR per day (100 µSv per day).).

Answer 13

a. 15 R per hour (150 mSv per hour).

Question 14

14. The focal spot in an X-ray tube:
    a. is inclined at an angle of 300 from normal to the tube axis.
    b. is maintained at a high negative voltage during operations.
    c. should be as large as possible to ensure a narrow beam of primary radiation.
    d. should be as small as possible without unduly shortening the life of the tube.

Answer 14

d. should be as small as possible without unduly shortening the life of the tube.

Question 15

15. In an X-ray tube, the filament and focusing cup are the two essential parts of the:
    a. anode.
    b. cathode.
    c. rectifier.
    d. X-ray transformer.

Answer 15

b. cathode.

Question 16

16. The quantity of radiation that will produce, by means of ionization, 1 electrostatic unit of electricity in 0.001293 g of dry air is known as a:
    a. millicurie.
    b. gamma
    c. roentgen.
    d. curie.

Answer 16

c. roentgen.

Question 17

17. The specific activity of an isotopic source is usually measured in:
    a. million electronvolts (MeV).
    b. curies per gram (Ci/g) [becquerel per gram (Bq/g)].
    c. roentgen per hour (R/h) [coulomb per kilogram (C/kg)].
    d. counts per minute (cpm).

Answer 17

b. curies per gram (Ci/g) [becquerel per gram (Bq/g)].

Question 18

18. Which of the following isotopes has the longest half-life?
    a. Tm-170
    b. Co-60
    c. Ir-192
    d. Cs-137

Answer 18

d. Cs-137

Question 19

19. The primary form of energy conversion when electrons strike a target in an X-ray tube results in the production of:
    a. primary X-rays.
    b. secondary X-rays.
    c. short wavelength X-rays.
    d. heat.

Answer 19

d. heat.

Question 20

20. The slope of a straight line joining two points of specified densities on a characteristic curve of a film is known as the:
    a. speed of the curve.
    b. latitude.
    c. average gradient.
    d. density.

Answer 20

c. average gradient.

Question 21

21. An X-ray film having wide latitude also has:
    a. poor definition.
    b. low contrast.
    c. high speed.
    d. high average gradient.

Answer 21

b. low contrast.

Question 22

22. The purpose for circulating oil in some types of X-ray tubes is to:
    a. lubricate moving parts.
    b. absorb secondary radiation.
    c. decrease the need for high current.
    d. dissipate heat.

Answer 22

d. dissipate heat.

Question 23

23. An X-ray tube with a small focal spot is considered better than one with a large focal spot when it is desired to obtain:
    a. greater penetrating power.
    b. better definition.
    c. less contrast.
    d. greater film density.

Answer 23

b. better definition.

Question 24

24. One method of reducing radiographic contrast is to:
    a. increase the distance between the radiation source and the object.
    b. decrease the distance between the object and the film.
    c. decrease the wavelength of the radiation used.
    d. increase development time within manufacturer’s recommendations.

Answer 24

c. decrease the wavelength of the radiation used.

Question 25

25. Thin sheets of lead foil in intimate contact with X-ray film during exposure increase film density because they: a. fluoresce and emit visible light, which helps expose the film. b. absorb the scattered radiation. c. prevent backscattered radiation from fogging the film. d. emit electrons when exposed to X-radiation and gamma radiation, which help darken the film.

Answer 25

d. emit electrons when exposed to X-radiation and gamma radiation, which help darken the film.

Question 26

26. X-ray tubes are often enclosed in a shockproof casing in order to: a. dissipate heat. b. protect the operator from high-voltage shock. c. shield the tube from secondary radiation. d. increase the efficiency of the rectifier.

Answer 26

b. protect the operator from high-voltage shock.

Question 27

27. The slope of the characteristic curve of a radiographic film is called: a. speed. b. latitude. c. gradient. d. density.

Answer 27

c. gradient.

Question 28

28. In X-ray radiography, alternating current must be changed to pulsating direct current in order to satisfy the need for unidirectional current. This change may be accomplished by: a. transformers. b. rectifiers. c. anodes. d. cathodes.

Answer 28

b. rectifiers.

Question 29

29. When radiographing to the 2-2T quality level, an ASTM IQI for 2.5 in. (63.5 mm) steel has a thickness of: a. 0.5 in. (12.7 mm) b. 0.0025 in. (0.064 mm) c. 0.005 in. (0.127 mm) d. 0.05 in. (1.27 mm)

Answer 29

d. 0.05 in. (1.27 mm)

Question 30

30. A good Co-60 radiograph is made on a 3 in. (76.2 mm) steel casting using an exposure time of 10 min and a source-to-film distance of 36 in. (914.4 mm). If it is necessary to change the source-to-film distance to 24 in. (609.6 mm), what exposure time would produce a similar radiograph if all other conditions remain the same? a. 1.6 min b. 4.4 min c. 6.4 min d. 8.8 min

Answer 30

b. 4.4 min

Question 31

31. When sharp, black, bird-foot shaped marks, which are known not to correspond with any discontinuities, appear at random on radiographs, they are probably caused by: a. prolonged development in old developer. b. exposure of the film by natural cosmic ray showers during storage. c. static charges caused by friction. d. inadequate rinsing after fixing.

Answer 31

c. static charges caused by friction.

Question 32

32. The adjustment of tube current in conventional X-ray tube circuits is made by: a. adjusting the current supplied to the filament. b. adjusting the target-to-cathode distance, c. inserting resistance in the anode lead. d. opening the shutter on the X-ray tube port.

Answer 32

a. adjusting the current supplied to the filament.

Question 33

33. In comparison with lower-voltage radiographs, high-energy radiographs show: a. greater contrast. b. greater latitude. c. greater amounts of scatter radiation relative to primary beam intensity. d. greater gradient.

Answer 33

b. greater latitude.

Question 34

34. Filters used at the port of the X-ray tube: a. intensify the X-ray beam by contributing secondary radiation. b. filter short wavelength X-ray beams to provide softer radiation. c. provide the most readily adjusted means of modifying X-ray intensity. d. filter out soft radiation to provide a more homogeneous X-ray beam.

Answer 34

d. filter out soft radiation to provide a more homogeneous X-ray beam.

Question 35

35. An ASTM IQI for use when inspecting a 0.5 in. (12.7 mm) thick steel plate to the 2-2T quality level using a 16 in. (406.4 mm) source-to-film distance would be made of: a. 0.005 in. (0.127 mm) thick aluminum. b. 0.05 in. (1.27 mm) thick aluminum or steel. c. 0.01 in. (0.254 mm) thick steel. d. 0.002 in. (0.051 mm) strip of any metallic material.

Answer 35

c. 0.01 in. (0.254 mm) thick steel.

Question 36

36. Filters placed between the X-ray tube and specimen tend to reduce scatter radiation, undercutting the specimen by: a. absorbing the longer wavelength components of the primary beam. b. absorbing the shorter wavelength components of the primary beam. c. absorbing backscatter radiation. d. decreasing the intensity of the beam.

Answer 36

a. absorbing the longer wavelength components of the primary beam.

Question 37

37. Besides serving as a filter, screens of high atomic numbers, such as lead and lead antimony, also: a. decrease the source-to-film distance needed for a proper radiograph. b. provide some image intensifying action. c. permit the use of higher speed film. d. decrease the graininess in a radiograph.

Answer 37

b. provide some image intensifying action.

Question 38

38. The range of thickness over which densities are obtained that are satisfactory for interpretation is a measure of the: a. subject contrast of a radiograph. b. sensitivity of a radiograph. c. latitude of a radiograph. d. definition of a radiograph.

Answer 38

c. latitude of a radiograph.

Question 39

39. Almost all gamma radiography is performed with: a. natural isotopes. b. Ir-192, co-60, or cs-137. c. radium. d. Tm-170.

Answer 39

b. Ir-192, co-60, or cs-137.

Question 40

40. The amount of unsharpness or blurring of a radiograph is: a. directly proportional to the object-to-film distance and inversely proportional to the size of the focal spot. b. directly proportional to the size of the focal spot and inversely proportional to the source-to-object distance. c. inversely proportional to the object-to-film distance and directly proportional to the source-to-object distance. d. inversely proportional to the size of the focal spot and the object-to-film distance.

Answer 40

b. directly proportional to the size of the focal spot and inversely proportional to the source-to-object distance.

Question 41

41. Images of discontinuities close to the source side of the specimen become less clearly defined as: a. source-to-object distance increases. b. the thickness of the specimen increases. c. the size of the focal spot decreases. d. the thickness of the specimen decreases.

Answer 41

b. the thickness of the specimen increases.

Question 42

42. X-ray films with large grain size: a. produce radiographs with better definition than film with small grain size. b. have slower speeds than those with a relatively small grain size. c. have higher speeds than those with a relatively small grain size. d. take longer to expose properly than film with relatively small grain size.

Answer 42

c. have higher speeds than those with a relatively small grain size.

Question 43

43. As the effective energy of the radiation increases: a. film graininess increases. b. film graininess decreases. c. radiographic definition increases. d. film speed decreases.

Answer 43

a. film graininess increases.

Question 44

44. The half-life of radioactive Cs-137 is nearest to: a. 36 days. b. 6 years. c. 30 years. d. 526 days.

Answer 44

c. 30 years.

Question 45

45. The most commonly used target material in an X-ray tube is: a. copper. b. carbon. c. carbide. d. tungsten.

Answer 45

d. tungsten

Question 46

46. The purpose for including a disk-shaped target that rotates rapidly during operation in some X-ray tubes is to: a. increase the intensity of X-radiation. b. decrease the voltage needed for a specific quality of radiation. c. increase the permissible load. d. decrease the intensity of X-radiation.

Answer 46

c. increase the permissible load.

Question 47

47. A device that is basically a combination of magnet and transformer designed to guide and accelerate electrons in a circular orbit to very high energies is called; a. an eleètrostatic belt generator. b. a linear accelerator. c. a betatron. d. a toroidal electromagnetic type X-ray tube.

Answer 47

c. a betatron.

Question 48

48. Two isotropic sources of a given strength have two different specific activity values. The source with the higher specific activity value will: a. have a smaller physical size than the source with a lower specific activity. b. have a shorter half-life than the source with a lower specific activity. c. produce harder gamma rays than the source with a lower specific activity. d. have a larger physical size than the source with the lower specific activity.

Answer 48

a. have a smaller physical size than the source with a lower specific activity.

Question 49

49. A gas-filled region located in an electrical field created by electrodes across which a potential difference is applied forms the major portion of: a. a low-voltage X-ray tube. b. a megger. c. a hot cathode X-ray tube. d. an ionization chamber.

Answer 49

d. an ionization chamber.

Question 50

50. Two serious obstacles to high-intensity fluoroscopy are: a. the inability to reproduce results and the need for periodic replacement of screens. b. the limited brightness and large grain size of fluoroscopic screens. c. cost and slow speed. d. the need for using long wavelength X-rays and the lack of X-ray intensity associated with this method.

Answer 50

b. the limited brightness and large grain size of fluoroscopic screens.

Question 51

51. In general, the quality of fluoroscopic equipment is best determined by: a. densitometer readings. b. IQI sensitivity measurements. c. discontinuity area measurements. d. reference standards.

Answer 51

b. IQI sensitivity measurements.

Question 52

52. In fluoroscopic testing, a fundamental difficulty is the relative low brightness level ofthe images. One method for increasing brightness uses that converts light energy from the initial phosphor surface to electrons, which are in turn accelerated and focused onto a smaller fluorescent screen. a. a betatron b. an electron amplifier c. an image amplifier or intensifier d. an electrostatic belt generator

Answer 52

c. an image amplifier or intensifier

Question 53

53. A general rule governing the application of the geometric principles of shadow formation states that the: a. X-rays should proceed from as large a focal spot as other considerations will allow. b. distance between the radiation source and the material examined should be as small as practical. c. film should be as far as possible from the object being radiographed. d. central ray should be as nearly perpendicular to the film as possible to preserve spatial relationships.

Answer 53

d. central ray should be as nearly perpendicular to the film as possible to preserve spatial relationships.

Question 54

54. The developer solution is: a. acidic. b. alkaline. c. saline. d. colloidal,

Answer 54

b. alkaline.

Question 55

55. The radiographic absorption of a material will tend to become less dependent upon the composition of the material when: a. the kilovoltage is increased. b. the source-to-film distance is decreased. c. the kilovoltage is decreased. d. a filter is used.

Answer 55

a. the kilovoltage is increased.

Question 56

56. The formula (milliamperes x time) + distance2 is: a. used to calculate film gradient. b. the reciprocity law. c. used to determine radiographic contrast. d. the exposure factor.

Answer 56

d. the exposure factor.

Question 57

57. The capacity that can be handled by an X-ray tube focal spot is governed by: a. the composition of the cathode. b. the size of the focal spot and the efficiency of the cooling system of the anode. c. the distance from the anode to the cathode. d. the high-voltage waveform.

Answer 57

b. the size of the focal spot and the efficiency of the cooling system of the anode.

Question 58

58. X-ray exposure holders and cassettes often incorporate a sheet of lead foil in the back, which is not in intimate contact with the film. The purpose of this sheet of lead foil is: a. to act as an intensifying screen. b. to protect the film from backscatter radiation. c. to support the holders and cassettes. d. not for specific use.

Answer 58

b. to protect the film from backscatter radiation.

Question 59

59. A lead sheet containing a pinhole may be placed halfway between the X-ray tube and the film in order to: a. determine the approximate size of the focal spot. b. measure the intensity of the central ray. c. filter scatter radiation. d. soften the X-radiation.

Answer 59

a. determine the approximate size of the focal spot.

Question 60

60. In certain cases, it may be advantageous to pack lead shot around a specimen. The purpose for doing this is to: a. prevent movement of the specimen. b. increase the subject contrast. c. generate smaller wavelength X-radiation. d. decrease the effect of scattered radiation undercutting the specimen.

Answer 60

d. decrease the effect of scattered radiation undercutting the specimen.

Question 61

61. When performing radiography on steel with a thickness less than 1 in. (25.4 mm): a. Co-60 would give greater radiographic sensitivity than a 250 kV X-ray machine. b. a 250 kv X-ray machine would give greater radiographic sensitivity than Co-60. c. the use of fluorescent screens would result in a radiograph of better quality than would lead foil screens. d. the use of lead foil screens will require a shorter exposure time than will fluorescent screens.

Answer 61

b. a 250 kv X-ray machine would give greater radiographic sensitivity than Co-60.

Question 62

62. A radiograph made with an exposure of 12 mA minutes has a density of 0.8 in the region of maximum interest. It is desired to increase the density to 2.0 in this area. By reference to a characteristic curve of the film, it is found that the difference in log E, between a density of 0.8 and 2.0, is 0.76. The antilogarithm of log 0.76 is 5.8. What must the new exposure time be to produce a radiograph with a density of 2.0? a. 9.12 mA minutes b. 21.12 mA minutes c. 69.6 mA minutes d. 16 mA minutes

Answer 62

c. 69.6 mA minutes

Question 63

63. The absorption of radiation by a material varies: a. directly with the square of the distance from the source. b. with the thickness of the material. c. inversely with the amount of scattering in the material. d. in an approximately exponential manner with the thickness of the material.

Answer 63

d. in an approximately exponential manner with the thickness of the material.

Question 64

64. The photoelectric effect involves: a. the visible electromagnetic spectrum. b. an electric camera. c. complete absorption of a photon. d. photodisintegration.

Answer 64

c. complete absorption of a photon.

Question 65

65. In order for a radiograph to have an IQI sensitivity of 2-2T or better: a. the radiographic procedure has to be able to differentiate a 2% difference in specimen thickness. b. the radiographic procedure must be able to define the 2T hole in an IQI that is 2% of the thickness of the specimen. c. the radiograph must be able to distinguish a discontinuity with a length equivalent to 2% of the specimen thickness. d. all the holes on the IQI must be seen on the radiograph.

Answer 65

b. the radiographic procedure must be able to define the 2T hole in an IQI that is 2% of the thickness of the specimen.

Question 66

66. For practical purposes, the shape of the characteristic curve of an X-ray film is: a. independent of the type of film used. b. independent of the quality of X-radiation or gamma radiation. c. drastically changed when the quality of X-ray radiation is changed. d. primarily determined by the subject contrast.

Answer 66

b. independent of the quality of X-radiation or gamma radiation.

Question 67

67. The interval between the time a film is placed in a fixer solution and the time when the original diffuse, yellow milkiness disappears is known as: a. clearing time. b. fixing time. c. hardening time. d. oxidation time.

Answer 67

a. clearing time.

Question 68

68. Improper geometric factors, poor contact between film and lead foil screens, and graininess of film are possible causes of: a. high film density. b. poor definition. c. fogged film. d. low film density.

Answer 68

b. poor definition.

Question 69

69. A radiograph of a steel weldment is made using a 15 MeV betatron. When the radiograph is developed, there is an overall film mottling. A possible cause for such mottling is: a. incorrect exposure time. b. excessive object-to-film distance. c. failure to use a lead screen during exposure. d. excessive exposure to ultraviolet rays.

Answer 69

c. failure to use a lead screen during exposure.

Question 70

70. A basic difference between a radiograph and a fluoroscopic image is: a. the fluoroscopic image is more sensitive. b. the fluoroscopic image is a positive whereas the radiograph is a negative transparency. c. the fluoroscopic image is brighter. d. negligible.

Answer 70

b. the fluoroscopic image is a positive whereas the radiograph is a negative transparency.

Question 71

71. A 1000 kVp X-ray machine used in conjunction with a lead foil screen has an approximate practical thickness limit of: a. 1.5 in. (38.1 mm) of steel or its equivalent. b. 3 in. (76.2 mm) of steel or its equivalent. c. 5 in. (127 mm) of steel or its equivalent. d. 16 in. (406.4 mm) of steel or its equivalent.

Answer 71

c. 5 in. (127 mm) of steel or its equivalent.

Question 72

72. Because of geometric factors such as source size, source-to-specimen distance, and specimen-to-film distance, there can be a lack of perfect sharpness at the edaes of indications. The unsharpness caused by geometrical factors may be referred to as the: a. astigmatic effect. b. penumbral shadow. c. focus variation. d. geometrical noise.

Answer 72

b. penumbral shadow.

Question 73

73. Two factors which greatly affect the suitability of the target material in an X-ray tube are: a. tensile strength and yield strength. b. melting point and magnetic strength. c. electrical resistance and tensile strength. d. atomic number and melting point.

Answer 73

d. atomic number and melting point.

Question 74

74. The reason the exposure time must be increased by a factor of four when the source-to-film distance is doubled is that: a. the intensity of radiation decreases at an exponential rate when the source-to-film distance is increased. b. the quality of radiation is inversely proportional to the square root of the distance from the source to the film. c. the intensity of radiation is inversely proportional to the square of the distance from the source to the film. d. the scattered radiation effect is greater as the source-to-film distance increases.

Answer 74

c. the intensity of radiation is inversely proportional to the square of the distance from the source to the film.

Question 75

75. The most important factor for determining the amount of X-ray absorption of a specimen is the: a. thickness of the specimen. b. density of the specimen. c. atomic nature of the material. d. Young's modulus of the material.

Answer 75

c. atomic nature of the material.

Question 76

76. The approximate radiographic equivalent factors for steel and copper at 220 kV are 1.0 and 1.4 respectively. If it is desirable to radiograph a 0.5 in. (12.7 mm) plate of copper, what thickness of steel would require about the same exposure characteristics? a. 0.7 in. (17.8 mm) of steel. b. 0.35 in. (8.9 mm) of steel. c. 1.4 in. (35.6 mm) of steel. d. 1.0 in. (25.4 mm) of steel.

Answer 76

a. 0.7 in. (17.8 mm) of steel.

Question 77

77. Which of the following technique variables is most commonly used to adjust subject contrast? a. Source-to-film distance. b. Milliamperage. c. Kilovoltage. d. Focal point size.

Answer 77

c. Kilovoltage.

Question 78

78. Films that are left between lead screens too long in a high-temperature and high-humidity atmosphere may: a. show increased speed but decreased quality characteristics. b. become fogged. c. become mottled. d. show tree-shaped light areas in the finished radiograph.

Answer 78

b. become fogged.

Question 79

79. The quantitative measure of film blackening is referred to as: a. definition. b. photographic density. c. film contrast. d. radiographic contrast,

Answer 79

b. photographic density.

Question 80

80. A curve that relates density with the logarithm of exposure or of relative exposure is called: a. a sensitivity curve. b. a density-exposure curve. c. a characteristic curve. d. an X-ray intensity curve.

Answer 80

c. a characteristic curve.

Question 81

81. Subject contrast is not affected by: a. thickness differences in the specimen. b. radiation quality. c. scattered radiation. d. film size.

Answer 81

d. film size.

Question 82

82. Which of the following instruments would exhibit the best sensitivity and most likely be used to detect small leaks in a radiation barrier? a. A film badge. b. A fountain-pen-type ionization chamber. c. A geiger counter. d. A dosimeter.

Answer 82

c. A geiger counter.

Question 83

83. At voltages above 400 kV, the use of lead to provide protection may present serious problems. If this is a serious problem, which of the following materials would most likely be used as a substitute? a. Aluminum. b. Concrete. c. Steel. d. Boron.

Answer 83

b. Concrete.

Question 84

84. A qualitative term often used to indicate the size of the smallest detail that can be seen in a radiograph is: a. radiographic sensitivity. b. radiographic definition. c. radiographic contrast. d. subject contrast.

Answer 84

a. radiographic sensitivity.

Question 85

85. The slope (steepness) of a characteristic curve is a measure of: a, subject contrast. b. radiographic definition. c. radiographic contrast. d. film contrast.

Answer 85

c. radiographic contrast.

Question 86

86. A special radiographic method requiring two radiographs taken during separate exposures from two different positions to give the visual impression of a three-dimensional display when viewed in an optical device simultaneously is called: a. fluoroscopy. b. xeroradiography. c. stereo radiography. d. parallel radiography.

Answer 86

c. stereo radiography.

Question 87

87. The depth of a discontinuity can be estimated by making two exposures on a single film from two different positions of the X-ray tube. The depth of the discontinuity is computed from the shift in the shadow of the discontinuity with respect to the images of fixed markers on the front and back of the specimen. The method is called: a. stereo radiography. b. xeroradiography. c. fluoroscopy d. the parallax method of depth location.

Answer 87

d. the parallax method of depth location.

Question 88

88. Agitation of the developer during the development process may: a. speed the developing cycle. b. help replenish the developer. c. cause undesirable, preferential flow of developer along certain paths. d. cause reticulation.

Answer 88

c. cause undesirable, preferential flow of developer along certain paths.

Question 89

89. The activity of the fixer diminishes after being used for a period of time because the: a. active ingredients evaporate. b. active ingredients are absorbed by the radiograph. c. fixer solution accumulates soluble silver salts. d. active ingredients settle to the bottom of the tank.

Answer 89

c. fixer solution accumulates soluble silver salts.

Question 90

90. In processing radiographs, the hourly flow of water in the wash tank should be: a. 2-3 times the volume of the tank. b. 4-8 times the volume of the tank. c. at least 40 gal (151.4 L) per hour. d. varied continuously in proportion to the number of radiographs being developed.

Answer 90

b. 4-8 times the volume of the tank.

Question 91

91. The equation for determining geometric unsharpness Ug is Ug/F = d/Do. Which change below will decrease the geometric unsharpness? a. Source-to-object distance decreases. b. Object-to-film distance increases. c. Size of radiation source decreases. d. Thickness of test specimen decreases.

Answer 91

c. Size of radiation source decreases.

Question 92

92. Increasing the X-ray or gamma-ray energy will: a. significantly decrease the average gradient of a characteristic curve, b. significantly increase the average gradient of a characteristic curve. c. increase the slope of a characteristic curve. d. have little effect on the shape of a characteristic curve.

Answer 92

d. have little effect on the shape of a characteristic curve.

Question 93

93. As the development time increases: a. the characteristic curve grows steeper and moves to the left. b. the characteristic curve grows steeper and moves to the right. c. the characteristic curve remains the same in shape but moves to the left. d. there is little effect on the characteristic curve.

Answer 93

a. the characteristic curve grows steeper and moves to the left.

Question 94

94. A distinctive characteristic of high-voltage radiography is that: a. it results in comparatively high subject contrast. b. it results in comparatively high radiographic contrast. c. it is applicable to comparatively thick or highly absorbing specimens. d. there is no contrast in high-voltage radiography.

Answer 94

c. it is applicable to comparatively thick or highly absorbing specimens.

Question 95

95. Lead screens are used for almost all exposures when using: a. the fluoroscopic technique. b. low-voltage radiography. c. high-voltage radiography. d. xeroradiography.

Answer 95

c. high-voltage radiography.

Question 96

96. Which of the following glasses would most likely be used as an X-ray barrier window on fluoroscopic equipment? a. Heat-resistant glass. b. Lead glass. c. Optical glass. d. Barium oxide glass.

Answer 96

b. Lead glass.

Question 97

97. Radiographic undercutting is caused by: a. side scatter. b. poor geometry. c. lead screens. d. free electrons.

Answer 97

a. side scatter.

Question 98

98. When other operating conditions are held constant, a change in tube current causes a change in radiation intensity emitted from an X-ray tube, the intensity being approximately proportional to tube current. What is the primary factor that prevents this from being exactly proportional? a. The voltage and voltage waveform of an X-ray machine transformer vary with load. b. Wavelength changes are not exactly proportional. c. Current cannot be changed at a linear rate. d. Scatter radiation does not vary at a proportional rate.

Answer 98

a. The voltage and voltage waveform of an X-ray machine transformer vary with load.

Question 99

99. When viewing a radiograph, an image of the back of the cassette superimposed on the image of the specimen is noted. This is most likely due to: a. undercut. b. overexposure. c. the X-ray intensity was too high. d. backscatter.

Answer 99

d. backscatter.

Question 100

100. The half-value layer of lead for Co-60 is approximately 0.5 in. (12.7 mm). If the radiation level on the source side of a 1.5 in. (38.1 mm) lead plate is 64 R/h (640 mSv/h), the radiation level on the opposite side is: a. 8 R/h (80 mSv/h) b. 21.33 R/h (213 mSv/h) c. 10.66 R/h (106 mSv/h) d. 32 R/h (320 mSv/h)

Answer 100

a. 8 R/h (80 mSv/h)

Question 101

101. Which of the following is not a factor in determining subject contrast? a. The nature of the specimen. b. The radiation quality used. c. The type of film used. d. Intensity and distribution of the scattered radiation.

Answer 101

c. The type of film used.

Question 102

102. If an exposure time of 60 s and a source-to-film distance of 4 ft (1.22 m) is necessary for a particular exposure, what exposure time would be needed for an equivalent exposure if the source-to-film distance is changed to 6 ft (1.83 m)? a. 27 s b. 49 s c. 135 s d. 400 s

Answer 102

c. 135 s

Question 103

103. Developer solution should be discarded when the quantity of replenisher added equals: a. the original quantity of developer. b. 2-3 times the original quantity of developer. c. 5-6 times the original quantity of developer. d. 10 times the original quantity of developer.

Answer 103

b. 2-3 times the original quantity of developer.

Question 104

104. If a specimen is radiographed at 40 kV and again at 50 kv with time compensation to give the radiographs the same density, which of the following statements would be true? a. The 40 kV exposure would have a lower contrast and a greater latitude than the 50 kV exposure. b. The 40 kV exposure would have a higher contrast and a greater latitude than the 50 kV exposure. c. The 50 kV exposure would have a lower contrast and a greater latitude than the 40 kV exposure. d. The 50 kv exposure would have a higher contrast and a greater latitude than the 40 kV exposure.

Answer 104

c. The 50 kV exposure would have a lower contrast and a greater latitude than the 40 kV exposure.

Question 105

105. A 250 kVp X-ray machine used in conjunction with a lead foil screen has an approximate practical thickness limit of: a. 1.5 in. (38.1 mm) of steel or its equivalent. b. 2.0 in. (50.8 mm) of steel or its equivalent. c. 6.0 in. (152.4 mm) of steel or its equivalent. d. 7.5 in. (190 mm) of steel or its equivalent.

Answer 105

b. 2.0 in. (50.8 mm) of steel or its equivalent.

Question 106

106. The degree of concentration of the radioactive material in a gamma-ray source is referred to as the: a. specific activity of the source. b. quality of the source. c. atomic weight of the source. d. half-life of the source.

Answer 106

a. specific activity of the source.

Question 107

107. In million-volt radiography, filtration at the tube: a. increases the generation of short wavelength X-rays. b. decreases the generation of short wavelength X-rays. c. improves the radiographic quality by decreasing scatter radiation. d. offers no improvement in radiographic quality.

Answer 107

d. offers no improvement in radiographic quality.

Question 108

108. Film selection for an X-ray exposure does not depend on: a. the thickness of the part. b. the material of the specimen. c. the voltage range of the X-ray machine. d. radiation absorption in the air.

Answer 108

d. radiation absorption in the air.

Question 109

109. While using an X-ray tube for radiography, the operator wants to increase the radiation intensity. To do so, the: a. kilovoltage should be lowered. b. tube current should be increased. c. test specimen should be moved farther from the film. d. tube current should be decreased.

Answer 109

b. tube current should be increased.

Question 110

110. Lead screens are put in direct contact with the film to: a. limit the photographic action on the film. b. absorb the shorter wavelength scattered radiation. c. intensify the photographic effect of the primary more than the scattered radiation. d. protect the film from poor handling.

Answer 110

c. intensify the photographic effect of the primary more than the scattered radiation.

Question 111

111. The main purpose of the X-ray generator controls on the equipment is to: a. maintain the direction and width of the X-ray beam. b. enable the operator to obtain the intensity, quality, and duration of exposure desired. c. allow the operator to adjust film focal distance remotely, d. change alternating current to increase X-ray intensity.

Answer 111

b. enable the operator to obtain the intensity, quality, and duration of exposure desired.

Question 112

112. When X-rays, gamma rays, light, or electrons strike the photographic emulsion, a change takes place in the silver halide crystals. This change is called: a. photographic density. b. photographic sensitivity. c. latent image. d. characteristic curve.

Answer 112

c. latent image

Question 113

113. With respect to quality, what three factors must be considered in selecting a source-to-film distance? a. Source activity, type of film, type of screens. b. Source activity, size of film, thickness of material. c. Source size, source activity, specimen-to-film distance. d. Source size, source side of object-to-film distance, required geometric unsharpness.

Answer 113

d. Source size, source side of object-to-film distance, required geometric unsharpness

Question 114

114. On a radiograph of a pipe weld, there is a very light irregularly shaped small image in the weld. This image would most likely be due to the presence of: a. porosity. b. slag inclusion. c. tungsten inclusion. d. inadequate buildup.

Answer 114

c. tungsten inclusion.

Question 115

115. A larger physical size source may produce an equivalent quality radiograph if: a. the source-to-film distance is increased. b. more backing lead is used. c. a faster film is used. d. exposure time is decreased.

Answer 115

a. the source-to-film distance is increased.

Question 116

116. A light image of a backing B on a processed radiograph is probably caused by: a. excessive density. b. backscatter. c. kilovoltage set too low. d. poor film handling.

Answer 116

b. backscatter.

Question 117

117. Co-59 becomes Co-60 when it is placed in a nuclear reactor where it captures: a. an electron. b. a neutron. c. a proton. d. contamination.

Answer 117

b. a neutron.

Question 118

118. When a faster speed film is substituted for a slower one to improve the economics of the exposure, which of the following conditions occurs? a. The film must receive special processing. b. The definition will improve. c. The image resolution will be reduced. d. It will have no effect on the radiograph.

Answer 118

c. The image resolution will be reduced.

Question 119

119. For a given change in the radiation exposure, film contrast is the inherent ability to show: a. a difference in density. b. no graininess. c. graininess. d. no appreciable change in density.

Answer 119

a. a difference in density.

Question 120

120. The ability of a material to block or partially block the passage of X-rays and gamma rays is called: a. penetration. b. absolution. c. absorption. d. latitude:

Answer 120

c. absorption.

Question 121

121. Source size, specimen thickness, and source-to specimen distance are the three factors that determine the: a. density of the radiograph. b. exposure of the radiograph. c. film size. d. unsharpness recorded on the radiograph.

Answer 121

d. unsharpness recorded on the radiograph

Question 122

122. The range of specimen thicknesses that can be adequately recorded on the radiograph is called: a. sensitivity of the radiograph. b. latitude of the radiograph. c. accuracy of the radiograph. d. intensity of the source.

Answer 122

b. latitude of the radiograph.

Question 123

123. Approximately how long would it take for a 10 Ci (370 GBq) Co-60 source to decay to 2.5 Ci (93 GBq)? a. 5.3 years b. 7.9 years c. 10.6 years d. 15.9 years

Answer 123

c. 10.6 years