McqMate
These multiple-choice questions (MCQs) are designed to enhance your knowledge and understanding in the following areas: Mechanical Engineering .
Chapters
| 51. |
Most significant difference in two X ray beams produced at different mA settings is: |
| A. | Penetrating power |
| B. | Wavelength distribution |
| C. | X ray quality |
| D. | Beam intensity |
| Answer» D. Beam intensity | |
| 52. |
Which of the following would be considered a film artifact? |
| A. | Excessive film density |
| B. | Insufficient film density |
| C. | Insufficient definition (penetrameter holes) |
| D. | Static marks |
| Answer» D. Static marks | |
| 53. |
Natural discontinuities comparable in size to the penetrameter holes shown on a radiograph may not be detected because: |
| A. | Natural discontinuities may contain less dense material than the penetrameter holes |
| B. | Natural discontinuities may be thicker than the penetrameter holes |
| C. | Natural discontinuities do not necessarily have as sharp edges as the penetrameter holes |
| D. | All of the above |
| Answer» C. Natural discontinuities do not necessarily have as sharp edges as the penetrameter holes | |
| 54. |
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)? |
| A. | 0.0625 Gy/h (6.25 R/h) |
| B. | 0.25 Gy/h (25 R/h) |
| C. | 16 Gy/h (1600 R/h) |
| D. | 4 Gy/h (400 R/h) |
| Answer» A. 0.0625 Gy/h (6.25 R/h) | |
| 55. |
Fluorescent screens are seldom used in industrial radiography because: |
| A. | Light leaks degrade the film image |
| B. | Film fogging can result if used in the vicinity of fluorescent lights |
| C. | Poor definition and screen mottle can result |
| D. | None of the above |
| Answer» C. Poor definition and screen mottle can result | |
| 56. |
Calculate geometric unsharpness for the following conditions: Source size = 2 mm × 2 mm; SFD = 700 mm; test piece thickness = 25 mm |
| A. | 0.6 mm |
| B. | 0.06 mm |
| C. | 6,0 mm |
| D. | 0.15 mm |
| Answer» D. 0.15 mm | |
| 57. |
The gamma factor of Ir-192 is: |
| A. | 1.37 R·h-1·Ci-1at one metre |
| B. | 0.59 R·h-1·Ci-1at one metre |
| C. | 0.0062 R·h-1·Ci-1at one metre |
| D. | 0.38 R·h-1·Ci-1at one metre |
| Answer» B. 0.59 R·h-1·Ci-1at one metre | |
| 58. |
A test piece with large differences in thickness would have: |
| A. | High film contrast |
| B. | High subject contrast |
| C. | Low subject contrast |
| D. | Low film contrast |
| Answer» B. High subject contrast | |
| 59. |
A quantity expressed by the formula, 0.693/(absorption co-efficient) is called: |
| A. | Half value layer |
| B. | Mass attenuation constant |
| C. | Half-life |
| D. | Specific activity |
| Answer» A. Half value layer | |
| 60. |
Which of the following techniques would probably reduce the amount of scattered radiation reaching the film during a radiographic exposure? |
| A. | Using a finer grained film |
| B. | Using a filtered X ray beam |
| C. | Removing lead screens |
| D. | All of the above |
| Answer» B. Using a filtered X ray beam | |
| 61. |
A radiographic indication in a weld, characterised by two parallel dark lines in the film image, would probably be caused by: |
| A. | Incomplete penetration |
| B. | Lack of fusion |
| C. | Slag inclusions |
| D. | Tungsten inclusions |
| Answer» B. Lack of fusion | |
| 62. |
To produce the sharpest image, which of the following should be true? |
| A. | The radiographic source should be small |
| B. | The radiographic source should be as close as possible to the test piece |
| C. | The planes of the test piece and the film should be at oblique angles to each other |
| D. | All of the above |
| Answer» A. The radiographic source should be small | |
| 63. |
‘Undercut’ or ‘burned out’ edges of the test piece film image are caused by: |
| A. | Geometric unsharpness |
| B. | Scattered radiation |
| C. | Inadequate source to film distance |
| D. | Old film |
| Answer» B. Scattered radiation | |
| 64. |
Which of the following is an advantage of gamma ray over X ray sources for radiography? |
| A. | Portability |
| B. | No external power supply needed |
| C. | Ruggedness |
| D. | All of the above |
| Answer» D. All of the above | |
| 65. |
The intensifying effects of fluorescent screens are caused by: |
| A. | Electron emission |
| B. | Light emission |
| C. | Secondary X rays |
| D. | All of the above |
| Answer» B. Light emission | |
| 66. |
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? |
| A. | 1/2 minute |
| B. | 1 minute |
| C. | 1.5 minutes |
| D. | 3 minutes |
| Answer» C. 1.5 minutes | |
| 67. |
The half-life of Cs-137 is approximately: |
| A. | 74 days |
| B. | 129 days |
| C. | 5.3 years |
| D. | 30.1 years |
| Answer» D. 30.1 years | |
| 68. |
Unacceptable radiographic film quality would be indicated by: |
| A. | Artifacts of known origin in the film's area of interest |
| B. | Use of a smaller penetrameter than required |
| C. | H & D density less than 2.0 |
| D. | All of the above |
| Answer» D. All of the above | |
| 69. |
Which of the following welding discontinuities would be most difficult to image radiographically: |
| A. | Porosity |
| B. | Lack of side wall fusion |
| C. | Undercut |
| D. | Slag inclusions |
| Answer» B. Lack of side wall fusion | |
| 70. |
The most important factor in limiting radiation exposure is: |
| A. | Time |
| B. | Distance |
| C. | Shielding |
| D. | All of the above |
| Answer» D. All of the above | |
| 71. |
The threshold energy below which pair production cannot occur is approximately: |
| A. | 100 keV |
| B. | 1 MeV |
| C. | 10 MeV |
| D. | 20 MeV |
| Answer» B. 1 MeV | |
| 72. |
A photon-electron interaction in which a photon gives up all its energy to an electron is called: |
| A. | The photoelectric effect |
| B. | The Compton effect |
| C. | Pair production |
| D. | Bremsstrahlung |
| Answer» A. The photoelectric effect | |
| 73. |
An acceptable quality radiograph should include: |
| A. | Proper identification |
| B. | Correct penetrameter and visible holes |
| C. | Location markers |
| D. | All of the above |
| Answer» D. All of the above | |
| 74. |
For gamma ray sources, radiographic intensity is proportional to source activity in gigabecquerels or curies for: |
| A. | All sources |
| B. | Large sources |
| C. | Small sources |
| D. | None of the above |
| Answer» A. All sources | |
| 75. |
Poor contact between lead screens and film is likely to cause: |
| A. | An indistinct or ‘fuzzy’ image |
| B. | A mottled appearance on the film |
| C. | ‘Undercut’ of the test piece image |
| D. | Increased geometric unsharpness |
| Answer» A. An indistinct or ‘fuzzy’ image | |
| 76. |
Which of the following conditions might cause mottling of a radiographic film? |
| A. | Test piece with thickness equal to an integral multiple of the primary beam wavelength |
| B. | Back scatter from aged fluorescent screens |
| C. | Test piece with thickness of the same order of magnitude as the grain size |
| D. | Test piece with thickness equal to an integral multiple of the average grain size |
| Answer» B. Back scatter from aged fluorescent screens | |
| 77. |
A photon-electron interaction in which a photon gives up a portion of its energy to an electron is called: |
| A. | The photoelectric effect |
| B. | The Compton effect |
| C. | Pair production |
| D. | Bremsstrahlung |
| Answer» B. The Compton effect | |
| 78. |
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)? |
| A. | 518 cm (17 feet) |
| B. | 16551 cm (543 feet) |
| C. | 8291 cm (272 feet) |
| D. | 17983 cm (590 feet) |
| Answer» A. 518 cm (17 feet) | |
| 79. |
It is important to initiate the welding arc within the weld groove because: |
| A. | Starting a weld bead outside the groove may overheat the base metal |
| B. | Too rapid heating and cooling of the base metal can cause hard spots which are potential failure initiation sites |
| C. | Starting a weld bead outside the groove results in excessively wide welds |
| D. | None of the above |
| Answer» D. None of the above | |
| 80. |
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)? |
| A. | 1676.4 cm (55 feet) |
| B. | 1981 cm (65 feet) |
| C. | 1524 cm (50 feet) |
| D. | 762 cm (25 feet) |
| Answer» C. 1524 cm (50 feet) | |
| 81. |
Which of the following techniques would probably reduce the amount of scattered radiation reaching the film during a radiographic exposure? |
| A. | Using a finer grained film |
| B. | Masking the test piece |
| C. | Removing lead screens |
| D. | All of the above |
| Answer» B. Masking the test piece | |
| 82. |
The lights in a high intensity viewer are typically: |
| A. | Fluorescent |
| B. | Normal incandescent bulbs |
| C. | Photoflood bulbs |
| D. | Mercury vapour lamps |
| Answer» C. Photoflood bulbs | |
| 83. |
The gamma factor of Cs-137 is: |
| A. | 1.37 R·h-1·Ci-1at one metre |
| B. | 0.59 R·h-1·Ci-1at one metre |
| C. | 0.0062 R·h-1·Ci-1at one metre |
| D. | 0.38 R·h-1·Ci-1 at one metre |
| Answer» D. 0.38 R·h-1·Ci-1 at one metre | |
| 84. |
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? |
| A. | 1/2 minute |
| B. | 1 minute |
| C. | 2 minutes |
| D. | 4 minutes |
| Answer» B. 1 minute | |
| 85. |
A thin, jagged, dark line inside the weld image on a radiographic film is probably: |
| A. | Incomplete penetration |
| B. | Lack of fusion |
| C. | Burn through |
| D. | A crack |
| Answer» D. A crack | |
| 86. |
A straight, dark line in the centre of a weld bead image on film would be suspected of being: |
| A. | Lack of fusion |
| B. | A crack |
| C. | Incomplete penetration |
| D. | Root concavity |
| Answer» C. Incomplete penetration | |
| 87. |
‘Undercut’ or ‘burned out’ edges of the test piece in film image can usually be reduced by: |
| A. | Increasing source to film distance |
| B. | Decreasing the thickness of the lead screens |
| C. | Placing a thin sheet of lead behind the cassette |
| D. | Masking the test piece |
| Answer» D. Masking the test piece | |
| 88. |
Which of the following would be detrimental to radiographic image sharpness? |
| A. | Small focal spot |
| B. | Large film focal distance |
| C. | Large object to film distance |
| D. | None of the above |
| Answer» C. Large object to film distance | |
| 89. |
Contrast and definition are the two major factors that determine the of the radiograph: |
| A. | Density |
| B. | Sensitivity |
| C. | Graininess |
| D. | Intensity |
| Answer» B. Sensitivity | |
| 90. |
Scatter radiation: |
| A. | Is not controllable |
| B. | Is controllable to some extent, but cannot be completely eliminated |
| C. | Can be eliminated completely by changing the kV |
| D. | Can be eliminated completely by using lead intensifying screens |
| Answer» B. Is controllable to some extent, but cannot be completely eliminated | |
| 91. |
Which of the following factors will affect the definition of the radiographic image? |
| A. | Intensity of radiation |
| B. | Film density |
| C. | Tube current |
| D. | Focal spot size |
| Answer» D. Focal spot size | |
| 92. |
Slow films: |
| A. | Give better definition than fast films |
| B. | Are faster than fast films |
| C. | Require shorter exposure times than fast films |
| D. | Usually have less contrast than fast films |
| Answer» A. Give better definition than fast films | |
| 93. |
Contrast is defined as the comparison between on different areas of the radiograph: |
| A. | Density |
| B. | Sensitivity |
| C. | Sharpness |
| D. | Latitude |
| Answer» A. Density | |
| 94. |
Definition is defined as the measure of the of the outline of the image in the radiograph. |
| A. | Density |
| B. | Sensitivity |
| C. | Sharpness |
| D. | Latitude |
| Answer» C. Sharpness | |
| 95. |
As radiation (X ray or gamma ray) energy is lowered: |
| A. | Radiation of longer wavelength and better penetration is produced |
| B. | Radiation of shorter wavelength and better penetration is produced |
| C. | Radiation of shorter wavelength and less penetration is produced |
| D. | Radiation longer wavelength and less penetration is produced |
| Answer» D. Radiation longer wavelength and less penetration is produced | |
| 96. |
Dark crescent-shaped indications on a radiographic film are most likely caused by: |
| A. | Crimping film after exposure |
| B. | Crimping film before exposure |
| C. | Sudden extreme temperature change while processing |
| D. | Warm or exhausted fixer |
| Answer» A. Crimping film after exposure | |
| 97. |
Lead screen are primarily used to: |
| A. | Improve the quality of the radiography by increasing the effect of scatter radiation |
| B. | Intensify the primary beam |
| C. | Decrease film graininess |
| D. | Reduce density of film |
| Answer» B. Intensify the primary beam | |
| 98. |
Static marks are most often caused by: |
| A. | Film bent when inserted in a cassette or holder |
| B. | Foreign material or dirt imbedded in screens |
| C. | Scratches on lead foil screens |
| D. | Improper film handling techniques |
| Answer» D. Improper film handling techniques | |
| 99. |
When radiographic energy is decreased: |
| A. | The subject contrast decreases |
| B. | The film contrast decreases |
| C. | The subject contrast increases |
| D. | The film contrast decreases |
| Answer» C. The subject contrast increases | |
| 100. |
The major cause for poor definition is: |
| A. | A source-to-film distance which is too long |
| B. | Screens which are too thin |
| C. | Film graininess |
| D. | Too small a source size |
| Answer» C. Film graininess | |
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