1. Which of the following would be detrimental to radiographic image sharpness?
Correct : B. Small film focal distance
2. A change in which the following parameters would require a new X ray exposure
chart?
Correct : B. X ray machine
3. If the required exposure time for a 1850 GBq (50 curie) Ir-192 source is 4 minutes,
what exposure time would be required for 925 GBq (25 curie) source:
Correct : B. 8 minutes
4. A radiograph is made using film X with an exposure of 10 mA-min. Film density obtained in the area of interest is 1.0. If it is desired to achieve a density of 2.0 in the area of interest, what exposure is required? (Log relative exposure = 1.1 for a density of 1.0 and 1.62 for a density of 2.0)
Correct : A. 41.67 mA-min
5. The least offensive of the following welding discontinuities would probably be:
Correct : D. Porosity
6. A quantity calculated by the formula, 0.693/(decay constant), is called:
Correct : C. Half-life
7. The density difference displayed from one area of a film radiograph to another is called:
Correct : B. Radiographic contrast
8. The half-life of Co-60 is approximately:
Correct : C. 5.3 years
9. Increasing the mA setting on an X ray machine:
Correct : A. Decreases exposure time
10. Which of the following would be considered a film artifact?
Correct : B. Light leaks
11. Which of the following would be detrimental to radiographic image sharpness?
Correct : B. Large film focal distance
12. The half-life of Ir-192 is approximately:
Correct : A. 74 days
13. A dark crescent shaped mark in the centre of a weld bead radiographic image would
probably be:
Correct : A. A film artifact
14. A photon-nuclear interaction in which energy is converted into sub-atomic particles is
called:
Correct : C. Pair production
15. An interaction in which radiation is produced by the rapid deceleration of an electron
is called:
Correct : D. Bremsstrahlung
16. The gamma factor of Tm-170 is:
Correct : C. 0.0062 R·h-1·Ci-1at one metre
17. An exposed radiographic film which transmits 1% of the light incident on it has what
density:
Correct : C. 99.0
18. If the radiation intensity is 5 Gy/h (500 R/h) at a distance of 152.4 cm (5 feet) from a
source, what is the intensity at 1524 cm (50 feet)?
Correct : D. 0.05 Gy/h (5 R/h)
19. The average energy of a Cs-137 source is approximately:
Correct : B. 660 keV
20. Which of the following is an advantage of X ray over gamma ray sources for
radiography?
Correct : C. Variable radiation energy
21. The basic purpose of a penetrameter is to:
Correct : A. Indicate quality of the radiographic technique
22. When a casting is being non destructively examined for critical service, and the
possibility of cracks exists, which of the following techniques would be best?
Correct : B. Magnetic Particle or Liquid Penetrant testing
23. Which of the following is an advantage of X ray over gamma ray sources for
radiography?
Correct : D. All of the above
24. The average energy of a T3-170 source is approximately:
Correct : A. 60-80 keV
25. The gamma factor of Co-60 is:
Correct : A. 1.37 R·h-1·Ci-1at one metre
26. The intensifying effect of lead screens is mainly caused by:
Correct : C. Excited electrons
27. Which of the following expressions correctly determines radiographic density?
Correct : B. Log (Io/It)
28. The most significant difference in two X ray beams produced at different kV settings
is:
Correct : C. Wavelength distribution
29. Most significant difference in two X ray beams produced at different mA settings is:
Correct : D. Beam intensity
30. Which of the following would be considered a film artifact?
Correct : D. Static marks
31. Natural discontinuities comparable in size to the penetrameter holes shown on a
radiograph may not be detected because:
Correct : C. Natural discontinuities do not necessarily have as sharp edges as the penetrameter holes
32. If the radiation intensity is 1 Gy/h (100 R/h) at a distance of 152.4 cm (5 feet) from a
source, what is the intensity at 610 cm (20 feet)?
Correct : A. 0.0625 Gy/h (6.25 R/h)
33. Fluorescent screens are seldom used in industrial radiography because:
Correct : C. Poor definition and screen mottle can result
34. Calculate geometric unsharpness for the following conditions: Source size = 2 mm × 2
mm; SFD = 700 mm; test piece thickness = 25 mm
Correct : D. 0.15 mm
35. The gamma factor of Ir-192 is:
Correct : B. 0.59 R·h-1·Ci-1at one metre
36. A test piece with large differences in thickness would have:
Correct : B. High subject contrast
37. A quantity expressed by the formula, 0.693/(absorption co-efficient) is called:
Correct : A. Half value layer
38. Which of the following techniques would probably reduce the amount of scattered
radiation reaching the film during a radiographic exposure?
Correct : B. Using a filtered X ray beam
39. A radiographic indication in a weld, characterised by two parallel dark lines in the film
image, would probably be caused by:
Correct : B. Lack of fusion
40. To produce the sharpest image, which of the following should be true?
Correct : A. The radiographic source should be small
41. ‘Undercut’ or ‘burned out’ edges of the test piece film image are caused by:
Correct : B. Scattered radiation
42. Which of the following is an advantage of gamma ray over X ray sources for
radiography?
Correct : D. All of the above
43. The intensifying effects of fluorescent screens are caused by:
Correct : B. Light emission
44. If the required X ray exposure time for a 225 kV, 5 mA exposure is 3 minutes,
approximately what exposure time would be required at 10 mA?
Correct : C. 1.5 minutes
45. The half-life of Cs-137 is approximately:
Correct : D. 30.1 years
46. Unacceptable radiographic film quality would be indicated by:
Correct : D. All of the above
47. Which of the following welding discontinuities would be most difficult to image
radiographically:
Correct : B. Lack of side wall fusion
48. The most important factor in limiting radiation exposure is:
Correct : D. All of the above
49. The threshold energy below which pair production cannot occur is approximately:
Correct : B. 1 MeV
50. A photon-electron interaction in which a photon gives up all its energy to an electron
is called:
Correct : A. The photoelectric effect
51. An acceptable quality radiograph should include:
Correct : D. All of the above
52. For gamma ray sources, radiographic intensity is proportional to source activity in
gigabecquerels or curies for:
Correct : A. All sources
53. Poor contact between lead screens and film is likely to cause:
Correct : A. An indistinct or ‘fuzzy’ image
54. Which of the following conditions might cause mottling of a radiographic film?
Correct : B. Back scatter from aged fluorescent screens
55. A photon-electron interaction in which a photon gives up a portion of its energy to an
electron is called:
Correct : B. The Compton effect
56. If the radiation intensity is 5.9 Gy/h (590 R/h) at a distance of 30.5 cm (1 foot) from a
source, how far is it to the point where the radiation intensity is 0.02 Gy/h (2R/h)?
Correct : A. 518 cm (17 feet)
57. It is important to initiate the welding arc within the weld groove because:
Correct : D. None of the above
58. If the radiation intensity is 5 Gy/h (500 R/h) at a distance of 152.4 cm (5 feet) from a
source, how far is it to the point where the radiation intensity is 0.05 Gy/h (5 R/h)?
Correct : C. 1524 cm (50 feet)
59. Which of the following techniques would probably reduce the amount of scattered
radiation reaching the film during a radiographic exposure?
Correct : B. Masking the test piece
60. The lights in a high intensity viewer are typically:
Correct : C. Photoflood bulbs
61. The gamma factor of Cs-137 is:
Correct : D. 0.38 R·h-1·Ci-1 at one metre
62. If the required X ray exposure time for a 150 kV, 5 mA exposure is 2 minutes,
approximately what exposure time would be required at 10 mA?
Correct : B. 1 minute
63. A thin, jagged, dark line inside the weld image on a radiographic film is probably:
Correct : D. A crack
64. A straight, dark line in the centre of a weld bead image on film would be suspected of
being:
Correct : C. Incomplete penetration
65. ‘Undercut’ or ‘burned out’ edges of the test piece in film image can usually be reduced by:
Correct : D. Masking the test piece
66. Which of the following would be detrimental to radiographic image sharpness?
Correct : C. Large object to film distance
67. Contrast and definition are the two major factors that determine the of
the radiograph:
Correct : B. Sensitivity
68. Scatter radiation:
Correct : B. Is controllable to some extent, but cannot be completely eliminated
69. Which of the following factors will affect the definition of the radiographic image?
Correct : D. Focal spot size
70. Slow films:
Correct : A. Give better definition than fast films
71. Contrast is defined as the comparison between on different areas of
the radiograph:
Correct : A. Density
72. Definition is defined as the measure of the of the outline of the
image in the radiograph.
Correct : C. Sharpness
73. As radiation (X ray or gamma ray) energy is lowered:
Correct : D. Radiation longer wavelength and less penetration is produced
74. Dark crescent-shaped indications on a radiographic film are most likely caused by:
Correct : A. Crimping film after exposure
75. Lead screen are primarily used to:
Correct : B. Intensify the primary beam
76. Static marks are most often caused by:
Correct : D. Improper film handling techniques
77. When radiographic energy is decreased:
Correct : C. The subject contrast increases
78. The major cause for poor definition is:
Correct : C. Film graininess
79. In order to increase latitude so that thick and thin portions may be radiographed at
reasonable viewing densities simultaneously:
Correct : C. The cassette may be loaded with two separate films of different speeds
80. A dark circle type indication appearing on a radiograph that is the result of the failure
of a core support to completely melt is called:
Correct : C. An unfused chaplet
81. Dark rounded indications with rather smooth edges appear on the radiograph of casting
made in sand mould. These indications would be interpreted as:
Correct : D. Gas holes
82. A dark, sharply defined, straight line in the centre of the weld, and running parallel with
the length of the weld should be interpreted as:
Correct : B. Incomplete penetration
83. A dark, jagged, linear indication appears on a radiograph of a casting. The area is a transition area between a thick and a thin section. This indication should be interpreted as:
Correct : A. A hot tear
84. In a radiograph of a weld there is an indication appearing at the end of the weldbead. It appears as a dark rounded indication with fine small tails coming from around the rounded indication giving it some what of a star-shaped appearance. This would probably be:
Correct : D. A star crack
85. The density of the radiograph through the weld area is 3.2 while the density in the base
metal is 2.9. This would probably indicate:
Correct : D. Weld underfill
86. When radiographing a part which contains a crack, it will appear on the radiograph as:
Correct : D. A dark linear indication which could be continuous or intermittent
87. If it were necessary to radiograph 18 cm (7 in.) thick steel product, which of the
following gamma ray sources would most be used?
Correct : D. Co–60
88. Almost all gamma radiography is performed with:
Correct : D. Ir-192 or Co-60
89. The half value layer of lead for Co-60 is approximately 13 mm (0.5 in). If the radiation level on the source side of a 38 mm (1.5 in) lead plate is 0.64 Gy/h (64 R/h):, the radiation level on the opposite side is:
Correct : D. 0.32 Gy/h (32 R/h).
90. The degree of concentration of the radioactive material in gamma ray sources is referred
to as the:
Correct : A. Atomic weight of the source
91. If 37 GBq (1 Ci), of Ir-92 produces dose rate of 0.59 Gy/h (59000 mR/h) at 30.5 cm (1
foot), how much dose in Gy/h (R/h) will 370 GBq (10 Ci) produce at the same distance?
Correct : C. 5.9 Gy/h (590,000 R/h)
92. Co-59 becomes Co-60 when it is placed in a nuclear reactor where it captures:
Correct : C. Neutron
93. Approximately how long would it take for a 370 GBq (10 Ci) Co-60 source to decay to
92.5 GBq (2.5 Ci)?
Correct : D. 10.6 years
94. The specific activity of radioactive isotope is expressed in:
Correct : B. Ci/g (Curies per gram) or Becquerel per kg
95. The general method of producing X rays involves the sudden deceleration of high
velocity electrons in a solid body called a:
Correct : C. Target
96. The velocity of electrons striking the target in an X ray tube is a function of:
Correct : C. The voltage applied
97. The primary form of energy conversion when an X ray tube is energized results in the
production of:
Correct : C. Short wavelength X ray
98. The radiation from 37 GBq (1 Ci) of Co-60 (0.145 Gy or 14.5R at 30.5 cm or 1 foot)
is attenuated in air to approximately 5mR/h at a distance of approximately:
Correct : B. 1524 cm (50 feet)
99. The standard dose rate of a radioactive isotope is expressed in:
Correct : C. Roentgens per hour at a distance of one foot
100. At 61 cm (two feet) from a radiation source, radiation intensity is 3 Gy/h (300 R/h).
What is the Intensity at 244 cm (8 feet) from the source?