RT Flashcards
Q/A
1
Q
- Although there may be other reasons for using calcium tungstate screens in industrial radiography, they are most usually used to:
a. improve definition and resolution in radiographic
images
b. improve contrast in radiographic images
c. decrease exposure time
d. make films respond to multimillion volt radiation
A
c. decrease exposure time
2
Q
- An excellent radiograph is obtained under given conditions of exposure with the film located at a distance of 91 cm (36 in.) from the target of the X-ray tube. If the film is now placed only 46 cm (18 in.) from the target, and all exposure conditions except time are held constant, the new exposure time will be:
a. unchanged
b. longer by approximately 80 percent
c. shorter by approximately 55 percent
d. only about 25 percent as long as the original exposure time
A
d. only about 25 percent as long as the original
exposure time
3
Q
- An excellent radiograph is obtained under given exposure conditions with a tube current of 5 mA and an exposure time of 12 minutes. If other conditions are not changed, what exposure time would be required if the X-ray tube current could be raised to 10mA?
a. 24 minutes
b. 12 minutes
c. 6 minutes
d. 3 minutes
A
c. 6 minutes
4
Q
- In film radiography, penetrameters are usually placed:
a. between the intensifying screen and the film
b. on the source side of the test object
c. on the film side of the test object
d. between the operator and the radiation source
A
b. on the source side of the test object
5
Q
- When radiographing to the 2-2T quality Ievel, an ASTM penetrameter for 13 mm (0.5 in.) thick 2024 aluminium alloy has a thickness of:
a. 13 mm (0.5 in.)
b. 5 x 10-5m (2 mils)
c. 13 x 10-5m (5 mils)
d. 25 X 10-5 m (10 mils)
A
d. 25 X 10-5 m (10 mils)
6
Q
- The penetrating ability of an X-ray beam is governed by:
a. kilovoltage
b. time
c. milliamperage
d. source-to-film distance
A
a. kilovoltage
7
Q
- Co-60 used in nondestructive testing emits:
a. alpha particles
b. neutrons
c. gamma rays
d. X-rays
A
c. gamma rays
8
Q
- A densitometer is an instrument for measuring:
a. X-ray intensity
b. film density
c. density of a material
d. tube current
A
b. film density
9
Q
- Three liquids which are essential to process an exposed film properly are:
a. stop bath, acetic acid, and water
b. developer, stop bath, and H2O2
c. developer, fixer, and water
d. acetic acid, fixer, and stop bath
A
c. developer, fixer, and water
10
Q
- The two most common causes for excessively high-density radiographs are:
a. insufficient washing and overdevelopment
b. contaminated fixer and insufficient washing
c. overexposure and contaminated fixer
d. overexposure and overdevelopment
A
d. overexposure and overdevelopment
11
Q
- The time required for one-half of the atoms in a particular sample of radioactive material to disintegrate is called:
a. the inverse square law
b. a curie
c. a half-life
d. the exposure time
A
c. a half-life
12
Q
- What does the term R/h refer to when speaking of intensity?
a. radiation limits for humans
b. roentgens per hour
c. X-rays per hour
d. radiation in hydrogen
A
b. roentgens per hour
13
Q
- The ability to detect a small discontinuity or flaw is called:
a. radiographic contrast
b. radiographic sensitivity
c. radiographic density
d. radiographic resolution
A
b. radiographic sensitivity
14
Q
- Movement, geometry, and screen contact are three factors that affect radiographic:
a. contrast
b. unsharpness
c. reticulation
d. density
A
b. unsharpness
15
Q
- The difference between the densities of two areas of a radiograph is called:
a. radiographic contrast
b. subject contrast
c. film contrast
d. definition
A
a. radiographic contrast
16
Q
- The most widely used unit of measurement for measuring the rate at which the output of a gamma ray source decays is the:
a. curie
b. roentgen
c. half-life
d. MeV.
A
a. curie
17
Q
- Exposure to X-rays or gamma rays:
a. may have acumulative effect which must be
considered
b. will be beneficial since they build up an immunity
to radiation poisoning
c. will have no effect on human beings
d. will have only a short-term effect on human
tissues
A
a. may have acumulative effect which must be
considered
18
Q
- Which dose would be dangerous, if not fatal, if applied to the entire body in a short period of time?
a. 1.5-15 R (4-38 x 10-4 C/kg)
b. 25-70R
c. 200-800 R
d. all of the above doses would most likely be fatal
A
c. 200-800 R
19
Q
- When doing gamma ray radiography with high-intensity emitters, the sources are best handled:
a. directly by personnel equipped with special
protective clothing
b. by remote handling equipment
c. directly by personnel with special protective
clothing except when radiographs are being
made
d. by the same methods used for low-intensity
emitters
A
b. by remote handling equipment
20
Q
- If a film is placed in a developer solution and allowed to develop without any agitation:
a. the radiograph will not show proper contrast
b. it will be impossible to fix the radiograph
permanently
c. there will be a general “fogging” condition over
the entire radiograph
d. there will be a tendency for areas to affect each
other
A
d. there will be a tendency for areas to affect each
other
21
Q
- The selection of the proper type of film to be used for the X-ray examination of a particular part depends on:
a. the thickness of the part
b. the material of the specimen
c. the voltage range of the available X-ray machine
d. all of the above
A
d. all of the above
22
Q
- A Co-60 source has a half-life of:
a. 1.2 years
b. 6 months
c. 5.3 years
d. 75 days
A
c. 5.3 years
23
Q
- X-ray tube current is controlled by:
a. the current passing through the filament
b. the distance from the cathode to the anode
c. the type of material used in the target
d. the voltage and waveform applied to the X-ray tube
A
a. the current passing through the filament
24
Q
- The voltage and waveform applied to the X-ray tube by a high-voltage transformer primarily determines the:
a. quantity of radiation
b. duration of exposure
c. penetrating ability
d. X-ray beam divergence
A
c. penetrating ability
25
25. Lead foil in direct contact with X-ray film:
a. intensifies the scatter radiation more than the
primary radiation
b. decreases the contrast of the radiographic image
c. intensifies the primary radiation more than the
scatter radiation
d. should not be used when gamma rays are
emitted by the source of radiation
c. intensifies the primary radiation more than the
scatter radiation
26
26. Fluorescent intensifying screens are usually mounted in pairs in rigid holders called:
a. film racks
b. cassettes
c. emulsifiers
d. diaphragms
b. cassettes
27
27. Radiographic sensitivity, in the context of the minimum detectable flaw size, depends on:
a. graininess of the film
b. the unsharpness of the flaw image in the film
c. the contrast of the flaw image on the film
d. all of the above
d. all of the above
28
28. In order to decrease geometric unsharpness:
a. radiation should proceed from as small a focal
spot as other considerations will allow
b. radiation should proceed from as large a focal
spot as other considerations will allow
c. the film should be as far as possible from the
object being radiographed
d. the distance from the anode to the material
examined should be as small as is practical
a. radiation should proceed from as small a focal
spot as other considerations will allow
29
29. As the kilovoltage applied to the X-ray tube is raised:
a. X-rays of longer wavelength and more
penetrating power are produced
b. X-rays of shorter wavelength and more penetrating
power are produced
c. X-rays of shorter wavelength and less penetrating
power are produced
d. X-rays of longer wavelength and less penetrating
power are produced
b. X-rays of shorter wavelength and more penetrating
power are produced
30
30. In order to increase the intensity of X-radiation:
a. the tube current should be increased
b. the tube current should be decreased
c. the test specimen should be moved farther from
the film
d. a lower kilovoltage should be applied to the tube
a. the tube current should be increased
31
31. Primary radiation which strikes a film holder or cassette through a thin portion of the specimen will cause scattering into the shadows of the adjacent thicker portions producing an effect called:
a. radiation imaging
b. spotting
c. undercut
d. unsharpness
c. undercut
32
33. Which of the following materials is suitable for use in vessels or pails and used to mix processing solutions?
a. stainless steel
b. aluminum
c. galvanized iron
d. tin
a. stainless steel
32
32. Scattered radiation caused by any material, such as a wall or floor, on the film side of the specimen is referred to as:
a. primary scattering
b. undercut
c. reflected scattering
d. backscattered radiation
d. backscattered radiation
33
34. Of the following, which would be especially sensitive to injury by excessive exposure to X-or gamma rays?
a. blood
b. lens of the eye
c. internal organs
d. all of the above
d. all of the above
34
35. X-ray exposure may be due to:
a. the direct beam from the X-ray tube target
b. scatter radiation arising from objects in the direct beam
c. both a and b
d. both a and b plus residual radiation that exists for the first few minutes after the X-ray machine has been returned to the "off'' position
c. both a and b
35
36. A general rule often employed for determining the kilovoltage to be used when X-raying a part is that:
a. the kilovoltage should be as high as other factors will permit
b. the kilovoltage should be as low as other factors will permit
c. the kilovoltage is always a fixed value and cannot be changed
d. the kilovoltage is not an important variable and can be changed over a wide range without affecting the radiograph
b. the kilovoltage should be as low as other factors will permit
36
If a piece of lead 13 mm (0.5 in.) thick is placed in the path of a beam of radiation emanating from Co-60, it will reduce the dose rate at a given location by:
a. one-third
b. one-quarter
c. one-half
d. three-quarters
c. one-half
37
38. Excessive exposure of film to light prior to development of the film will most likely result in:
a. a foggy film
b. poor definition
c. streaks
d. yellow stain
a. a foggy film
38
39. Reticulation resulting in a puckered or net-like film surface is probably caused by:
a. crimping film after exposure
b. sudden extreme temperature change while processing
c. water or developer on unprocessed film
d. excessive object-to-film distance
b. sudden extreme temperature change while processing
39
40. Frilling or loosening of the emulsion from the base of the film is most likely caused by:
a. water or developer on unprocessed film
b. low temperature of processing solutions
c. developer solution contamination
d. warm or exhausted fixer solution
d. warm or exhausted fixer solution
40
41. If an exposure time of 60 seconds was necessary using a 1.2 m_(4 ft) source-to-film distance for a particular exposure, what time would be necessary if a 0.6 m (2 ft) source-to-film distance is used and all other variables remain the same?
a. 120 s
b. 30s
c. 15 s
d. 240s
c. 15 s
41
42. One of the general rules concerning the application of geometric principles of shadow formation to radiography is:
a. the X-rays should proceed from as large a focal
spot as other considerations will allow
b. the film should be as far as possible from the object
being radiographed
c. the distance between the anode and the material
examined should always be as great as possible
d. all of the above
c. the distance between the anode and the material
examined should always be as great as possible
42
43. As a check on the adequacy of the radiographic
technique, it is customary to place a standard test piece on the source side of the specimen. This standard test piece is called a:
a. reference plate
b. lead screen
c. penetrameter
d. illuminator
c. penetrameter
43
44. The duration of an exposure is usually controlled by:
a. controlling the milliamperage
b. a timer
c. controlling the source-to-film distance
d. a choke coil in the filament transfonner
b. a timer
44
45. A penetrameter is used to indicate the:
a. size of discontinuities in a part
b. density of the film
c. amount of film contrast
d. quality of the radiographic technique
d. quality of the radiographic technique
45
46. A fluorescent intensifying screen will:
a. transform X-ray energy into visible or ultraviolet
light
b. result in reticulation
c. decrease the graininess of the image when using
gamma rays
d. increase the definition in a radiograph
a. transform X-ray energy into visible or ultraviolet
light
46
47. The three main steps in processing a radiograph are:
a. developing, frilling, and fixation
b. developing, fixation, and washing
c. exposure, developing, and fixation
d. developing, reticulating, and fixation
b. developing, fixation, and washing
47
48. Kilovoltage, exposure time, and source-to-film distance are three of the most important X-ray exposure factors that can be controlled. A fourth such exposure factor is:
a. focal point size
b. temperature
c. filament-to-focal spot distance
d. milliamperage
d. milliamperage
48
49. When the minute silver grains on which the X-ray film image is formed group together in relatively large masses, they produce a visual impression called:
a. air bells
b. graininess
c. reticulation
d. frilling
b. graininess
49
50. Static marks, which are black tree-like or circular marks on a radiograph, are often caused by:
a. film being 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
d. improper film handling techniques
50
51. The purpose of agitating an X-ray film during developrnent is to:
a. protect the film from excessive pressure
b. renew the developer at the surface of the film
c. disperse unexposed silver grains on the film surface
d. prevent reticulation
b. renew the developer at the surface of the film
51
52. When manually processing films, the purpose for sharply tapping hangers two or three times after the films have been lowered into the developer is to:
a. disperse unexposed silver grains on the film surface
b. prevent frilling
c. dislodge any air bubbles clinging to emulsion
d. do all of the above
c. dislodge any air bubbles clinging to emulsion
52
53. The activity of the developer solution is maintained stable by:
a. constantly agitating it
b. maintaining processing solutions within the recommended temperature range
c. avoiding contamination from the wash bath
d. adding replenisher
d. adding replenisher
53
55. For best results when manually processing film, solutions should he maintained within a temperature range of:
a. 18 to 24 ºC (65 to 75 ºF)
b. 65 to 75 ºC (149 to 167 ºF)
c. 24 to 29 ºC (75 to 85 ºF)
d. 75 to 85 ºC (167 to 185 ºF)
a. 18 to 24 ºC (65 to 75 ºF)
53
54. The purpose of fixation is:
a. to remove all the undeveloped silver salts of the
emulsion
b. to leave the developed silver as a permanent image
c. to harden the gelatin
d. all of the above
d. all of the above
53
56. Water spots on films can be minimized by:
a. the rapid drying of wet film
b. using a wetting agent solution
c. using a fresh fixer solution
d. cascading water during the rinse cycle
b. using a wetting agent solution
54
57. The small area in the X-ray tube from which the radiation emanates is called the:
a. diaphragm
b. focal spot
c. focusing cup
d. cathode
b. focal spot
55
58. The radiation quality of a gamma ray source is:
a. determined by the size of the focal spot
b. determined by the isotope involved
c. varied by the operator
d. greater in lr-192 than in Co-60
b. determined by the isotope involved
56
59. The most common material used to provide
protection against X-rays is:
a. high-density brick
b. an alloy of 70 percent steel and 30 percent copper
c. tungsten
d. lead
d. lead
57
60. A curie is the equivalent of:
a. 0.001 mCi
b. 1000 mCi
c. 1000 MCi
d. 100 MCi
b. 1000 mCi
58
61. With a given exposure time and kilovoltage, a
properly exposed radiograph is obtained with a
6 mA-minutes exposure at the distance of 51 cm
(20 in.). It is desired to increase the sharpness of
detail in the image by increasing the source-to-film
distance to 102 cm (40 in.). The correct milliamperage-minutes exposure to obtain the desired radiographic density at the increased distance is:
a. 12 mA-minutes
b. 24 mA-minutes
c. 3 mA-minutes
d. 1.7 mA-minutes
b. 24 mA-minutes
59
62. Very short wavelength electromagnetic radiation
produced when electrons travelling at high speeds
collide with matter is called:
a. X-radiation
b. beta radiation
c. gamma radiation
d. none of the above
a. X-radiation
60
63. The exposure of personnel to X- and gamma radiation can be measured or monitored by means of:
a. film badges
b. dosimeters
c. radiation exposure survey meters
d. all of the above
b. dosimeters
61
64. Assuming that a good radiograph is obtained at a
setting of 10mA in 40 s, how much time will be
necessary to obtain one equivalent radiograph if the
milliamperage is changed to 5 mA (all other
conditions remaining constant)?
a. 20s
b. 10 s
c. 80 s
d. 160 s
c. 80 s
62
65. A graph showing the relation between material thickness, kilovoltage, and exposure is called:
a. a bar chart
b. an exposure chart
c. a characteristic curve
d. an H&D curve
b. an exposure chart
63
66. A graph which expresses the relationship between the logarithm of the exposure applied to a photographic material and the resulting photographic density is called:
a bar chart
b. an exposure chart
c. the characteristic curve
d. a Iogarithmic chart
c. the characteristic curve
64
67. Short wavelength electromagnetic radiation produced y during the disintegration of nuclei of radioactive substances is called:
a. X-radiation
b. gamma radiation
c. scatter radiation
d. backscatter radiation
b. gamma radiation
65
68. A photographic image recorded by the passage of X or gamma rays through a specimen onto a film is
called a:
a. fluoroscopic image
b. radiograph
c. isotopic reproduction
d. none of the above
b. radiograph
66
69. The normal development time for manually
processing X-ray film is:
a. 12-18 minutes in processing solutions at 24 ºC
(75 ºF)
b. 3-8 minutes in processing solutions at 16 ºC (60 ºF)
c. 12-18 minutes in processing solutions at 68 ºC
(154 ºF)
d. 5-8 minutes in processing solutions at 20 ºC (68 ºF)
d. 5-8 minutes in processing solutions at 20 ºC (68 ºF)
67
70. In order to achieve uniformity of development over the area of an X-ray film during manual processing:
a. the film should be placed in a dryer after being
developed
b. the developer should be agitated by using
mechanical stirrers or circulating pumps
c. the film should be agitated while in the developer
d. the film should be transferred directly from the
developer to the fixer
c. the film should be agitated while in the developer
68
71. When referring to a "2T" or "4T" hole in the ASTM penetrameter, the T refers to the:
a. part thickness
b. penetrameter thickness
c. time of exposure
d. time for developing
b. penetrameter thickness
69
72. A sheet of lead with an opening cut in the shape of the part to be radiographed may be used to decrease the effect of scattered radiation which undercuts the specimens. Such a device is called a:
a. mask
b. filter
c. backscatter absorber
d. lead foil screen
a. mask
70
74. Fluoroscopy differs from radiography in that:
a. fluoroscopy uses a much lower kilovoltage than
radiography
b. fluoroscopy is much more sensitive than
radiography
c. the X-ray image is observed visually on a fluorescent
screen rather than recorded on a film
d. fluoroscopy permits examination of thicker parts
than does radiography
c. the X-ray image is observed visually on a fluorescent
screen rather than recorded on a film
71
73. Two X-ray machines operating at the same nominal kilovoltage and milliamperage settings:
a. will produce the same intensities and qualities of
radiation
b. will produce the same intensities but may produce
different qualities of radiation
c. will produce the same qualities but may produce
different intensities of radiation
d. may give not only different intensities but also
different qualities of radiation
d. may give not only different intensities but also
different qualities of radiation
72
75. An advantage of the pocket dosimeter type of ionization chamber used to monitor radiation received by personnel is:
a. it provides a permanent record of accumulated dosage
b. it provides an immediate indication of dosage
c. it is the most sensitive detector available
d. all of the above are advantages
b. it provides an immediate indication of dosage
73
76. The density difference between two selected portions of a radiograph is known as:
a. unsharpness
b. radiographic contrast
c. specific activity
d. subject density
b. radiographic contras
74
77. One requirement for keeping fluorescent screens in good condition is that they must:
a. be cleaned with a lint-free cloth each time they are used
b. not be exposed to intense ultraviolet radiation
c. be mounted in a rigid container at all times
d. not be exposed to caustic fumes
b. not be exposed to intense ultraviolet radiation
75
78. In making an isotope exposure in an unshielded area, you find the dose rate 1.8 m (6 ft) from the source is 1 200 mR/h. What would be the dose rate at 7.3 m
(24 ft)?
a. 75 mR/h
b. 100 mR/h
c. 200 mR/h
d. 300 mR/h
a. 75 mR/h
76
79. The intensity of X- or gamma radiation is measured in:
a. roentgens
b. ergs
c. roentgens per unit of time
d. H&D units
c. roentgens per unit of time
77
80. When producing radiographs, if the kilovoltage is increased, the:
a. subject contrast decreases
b. film contrast decreases
c. subject contrast increases
d. film contrast increases
a. subject contrast decreases
78
81. The accidental movement of the specimen or film during exposure or the use of a focus-film distance that is too small will:
a. produce a radiograph with poor contrast
b. make it impossible to detect large discontinuities
c. result in unsharpness of the radiograph
d. result in a fogged radiograph
c. result in unsharpness of the radiograph
79
82. A properly exposed radiograph that is developed in a developer solution at a temperature of 14 ºC (58 ºF) for 5 minutes will probably be:
a. overdeveloped
b. underdeveloped
c. fogged
d. damaged by frilling
b. underdeveloped
80
83. A good radiograph is obtained using a milliamperage of 15 mA and an exposure time of 0.5 minutes. What exposure time will be necessary to produce an equivalent radiograph if the milliamperage is changed to milliamperes and all other conditions remain the same?
a. 4.5 minutes
b. 1.5 minutes
c. 3 minutes
d. 0.5 minutes
b. 1.5 minutes
81
84. Lead screens in contact with the film during exposure:
a. increase the photographic action on the film largely by reason of the electron emission and partly by the secondary X-rays generated in the lead
b. absorb the shorter wavelength scattered radiation more than the long wavelength primary radiation
c. intensify the photographic effect of the scatter radiation more than that of the primary radiation
d. none of the above
a. increase the photographic action on the film largely by reason of the electron emission and partly by the secondary X-rays generated in the lead
82
85. The sharpness of the outline in the image of the radiograph is a measure of:
a. subject contrast
b. radiographic definition
c. radiographic contrast
d. film contrast
b. radiographic definition
83
86. An unshielded isotope source gives a dosage rate of 900 mR/h at 3 m (10 ft). What would the unshielded dosage rate be at 9 m (30 ft)?
a. 300mR/hr
b. 600mR/hr
c. 100 mR/hr
d. 2700 mR/hr
c. 100 mR/hr
84
87. Which has the shortest wavelengths?
a. visible light
b. microwaves
C.100 kV peak X-rays
d. infrared radiation
C.100 kV peak X-rays
85
88. Beta particles are:
a. neutrons
b. protons
c. electrons
d. positrons
c. electrons
86
89. A radioactive source with an activity of 1 Ci has:
a. 1 000 disintegrations per second taking place
b. 1 000 000 disintegrations per second taking place
c. 1 000 000 000 disintegrations per second taking place
d. 3.7 x 10-10 disintegrations per second taking place
d. 3.7 x 10-10 disintegrations per second taking place
87
90. The formula for determining permissible accumulated personnel dose is:
a. 12 (N - 18)
b. 18(5+N)
c. 5 (N - 18)
d. 12(N+18)
c. 5 (N - 18)
88
91. The metal that forms the image on an X-ray film is:
a. tin
b. silver
c. tungsten
d. iron
b. silver
89
92. Unexposed boxes of X-ray film should be stored:
a. flat
b. on edge or end
c. in a pile
d. it does not matter
b. on edge or end
90
93. The lead symbol "B" is attached to the back of the film holder to determine:
a. sensitivity
b. whether excessive backscatter is present
c. radiographic contrast
d. density
b. whether excessive backscatter is present
91
94. Penetrameters for ____ are considered Group I Materials and do not need to have an identification notch.
a. inconel
b. nickel
c. stainless steel
d. aluminum bronze
c. stainless steel
92
95. The purpose of a dated decay curve is to:
a. determine the source size at any time
b. calculate shielding requirements
c. determine the source strength (activity) at any time
d. mark the date and length of time for each exposure
c. determine the source strength (activity) at any time
93
96. Why is Co-60 used as a radiation source for mediumweight metals of thickness ranges from 38 to 229 mm ( 1.5 to 9 in.)?
a. because of its short half-life
b. because of the limited amount of shielding required
c. because of its penetrating ability
d. none of the above
c. because of its penetrating ability
94
97. The cause for poor image definition could be:
a. too short source-to-film distance
b. screens and film not in close contact
c. film graininess
d. all of the above
d. all of the above
95
98. During manual film processing, the purpose of the stop bath is to:
a. change the exposed silver salts to black metallic silver
b. neutralize the developer and stop the developing process
c. eliminate most water spots and streaks
d. none of the above
b. neutralize the developer and stop the developing process
96
99. A thin metallic sheet (brass, copper, aluminum, etc.) placed at the source to reduce effects of softer radiation is known as:
a. an intensifying screen
b. a filter
c. an electron inducer
d. a focusing cup
b. a filter
97
100. The reason a "shim" is used in radiographic setup is to:
a. improve the penetrameter image
b. reduce diffraction
c. simulate weld reinforcement
d. intensify the image
c. simulate weld reinforcement
98
101. The focal spot size of an X-ray machine must be known in order to determine the:
a. geometric unsharpness value
b. kilovolt peak output
c. milliamperage settings
d. exposure time
a. geometric unsharpness value
99
102. A section with a significant increase in thickness variation is required to be shown on a single radiograph within a desired film density range. This may be accomplished by:
a. increasing kilovoltage
b. using a coarser grain film
c. both a and b
d. neither a nor b
a. increasing kilovoltage
100
103. The density of a radiograph image refers to the:
a. thickness of the film
b. thickness of the specimen
c. weight of the film
d. degree of film blackening
d. degree of film blackening
101
104. A beam of radiation consisting of a single wavelength is known as:
a. characteristic radiation
b. fluoroscopic radiation
c. monochromatic radiation
d. microscopic radiation
c. monochromatic radiation
102
105. The image of the required penetrameter and hole on the radiograph indicates that the radiograph has the required:
a. contrast
b. definition
c. sensitivity
d. latitude
c. sensitivity
103
106. The primary parts of an atom are:
a. proton, neutrino, electron
b. proton, electron, gamma ray
c. photon, electron, neutron
d. proton, electron, neutron
d. proton, electron, neutron
104
107. X-rays and gamma rays always travel in:
a. pairs
b. orbital spheres
c. straight lines
d. none of the above
c. straight lines
105
108. A large source size can be compensated for by:
a. increasing the source-to-specimen distance
b. addition of Iead screens
c. increasing the specimen-to-film distance
d. increasing penumbra
a. increasing the source-to-specimen distance
106
109. Radiation arising directly from the target of an X-ray tube or an accelerator, or from a radioactive source, is usually referred to as:
a. secondary radiation
b. primary radiation
c. backscatter
d. inherent radiation
b. primary radiation
107
110. The extent to which X-rays can be successfully utilized in nondestructive testing is largely dependent upon:
a. the intensity of the X-rays generated
b. their wavelengths
c. the dimensions of the area from which they are emitted
d. the duration of their emission
e. all of the above
c. the dimensions of the area from which they are emitted
108
111. To produce X-rays, electrons are accelerated to a high velocity by an electrical field and then suddenly stopped by a collision with a solid body. This body is called a:
a. cathode
b. filament
c. target
d. generator
c. target
109
112. The best X-ray efficiency is produced when the target material has a:
a. low atomic number
b. high atomic number
c. low hardness
d. high hardness
b. high atomic number
110
113. What is sometimes used to change the altemating current from the high voltage transformer to direct current for the purpose of increasing the X ray machine output?
a. rectifier
b. cathode X-ray tubes
c. gas X-ray tube
d. vacuum X-ray tube
a. rectifier
111
114. In X-radiography, the ability to penetrate the test object is govemed by:
a. source-to-film distance
b. time
c. kilovoltage
d. milliamperage
c. kilovoltage
112
115. Which of the following types of radiation is emitted by Co-60 and used in nondestructive testing?
a. neutrons
b. gamma rays
c. X-rays
d. alpha particles
b. gamma rays
113
116. The term used to describe the loss of excess energy by the nucleus of radioactive atoms is called:
a. decay (disintegration)
b. ionization
c. scintillation
d. activation
a. decay (disintegration)
114
117. X-rays, gamma rays, and alpha particles all have one thing in common; they are all:
a. particulate radiations
b. electromagnetic radiations
c. microwave radiations
d. ionizing radiations
d. ionizing radiations
115
118. The term used to express the number of curies of radioactivity per gram or ounce of source weight is:
a. decay
b. emissivity
c. specific activity
d. source output
c. specific activity
116
119. Atoms, molecules, and various subatomic particles that carry either a positive or negative electrical charge are called:
a. photoelectrons
b. photons
c. ions
d. compounds
c. ions
117
120. Gamma and X-radiation interact with matter and may be absorbed by:
a. photoelectric absorption
b. Compton scattering
c. pair production
d. all of the above
d. all of the above
118
121. Approximately what percent of the original radioactivity is left after 6 half-lives?
a. 0.005
b. 10
c. 33.3
d. 2
d. 2
119
123. The radiation intensity of a radioisotope:
a. increases with time
b. decreases with time
c. is not affected as time elapses
d. none of the above
b. decreases with time
119
122. The velocity of all electromagnetic radiation is:
a. 186 000 miles per second
b. 18 600 miles per second
c. 186 000 miles per second
d. 1 860 miles per second
a. 186 000 miles per second
120
Absorption is increased as the:
atomic number and density of the absorber increase
