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49 Cards in this Set
- Front
- Back
Because of geometrical factors such as source size, source to specimen distance, and specimen to film distance, there can be a lack of perfect sharpness at the edges of indications. The unsharpness caused by these factors may be referred to as the:
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Penumbral shadow
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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:
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Clearing time.
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Which of the following is not a factor in determining subject contrast?
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Type of film used
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Approximately how long would it take for a 10-curie cobalt 60 source to decay to 2 1/2 curies?
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10.6 years
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The two most common causes for excessively high density radiographs are:
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Over exposure and over development
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The ability to detect a small discontinuity of flaw is called
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radiographic density
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The selection of the proper type of film to be used for the radiographic examination of a particular part depends on
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the strength of the radioactive source
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The half value layer of lead for cobalt 60 is approximately 0.5 inch. If the radiation level on the source side of a 1.5-inch lead plate is 64 R/hr, the radiation level on the opposite side is:
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8 R/hr.
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order for a radiograph to have a penetrameter sensitivity of 2 2T or better:
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The radiographic procedure must be able to define the 2T hole in a penetrameter that is 2 percent of the thickness of the specimen.
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Films that are left between lead screens too long in a high temperature and high humidity atmosphere may:
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Become fogged
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larger physical size source may produce an equivalent quality radiograph if:
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The source to film distance is increased
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If it were necessary to radiograph a 7-inch thick steel product, which of the following gamma ray sources would most likely be used?
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Cobalt-60
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One method of reducing radiographic contrast is to:
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Decrease the wavelength of the radiation used.
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A general rule governing the application of the geometric principles of shadow formation states that:
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The central ray should be a nearly perpendicular to the film as possible, to preserve spatial relationships.
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Lead foil in direct contact with film
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intensifies the primary radiation more than the scatter radiation
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The quantitative measure of film blackening is referred to as
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Photographic density
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Radiographic sensitivity, in the context of the minimum detectable flaw size, depends on
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the unsharpness
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In order to decrease Ug:
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radiation should proceed from as small a focal spot as possible
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If an exposure time of 60 seconds and a source to film distance of 48 inches 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 24 inches.
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15 seconds
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Radiographic undercutting is caused by
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Side scatter
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If one curie of iridium-192 produces a dose rate of 5900 mR per hour at one foot, how many mR will ten curies produce at the same distance?
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59,000
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Subject contrast is affected by
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Thickness differences in specimen, Radiation quality, Scattered radiation.
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The absorption of gamma rays from a given source when passing through matter depends on
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The atomic number, density, and thickness of the matter
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The projected area of the target of an X ray tube is called
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Effective focal spot
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When a faster speed film is substituted for a slower one to improve the economics of the exposure, which of the following conditions occur?
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The image resolution will be reduced
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Which of the following instruments would exhibit the best sensitivity and most likely be used to detect small leaks in a radiation barrier?
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A survey meter
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specific activity of an isotopic source is usually measured in:
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Curies per gram
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The focal spot in an X ray tube:
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Should be as small as possible without unduly shortening the life of the tube.
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Almost all gamma radiography is performed with:
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Iridium 192 or cobalt 60
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The range of thickness over which densities are obtained that are satisfactory for interpretation is a measure of the:
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Latitude of a radiograph
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When X rays, gamma rays, light, or electrons strike the photographic emulsion, a change takes place in the silver crystals. This change is referred to as:
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Latent image
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The developer solution is:
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Alkaline
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Unexposed boxes of X-ray film should be stored:
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On edge or end
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The purpose of agitating the X-ray film during development is to:
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Renew the developer at the surface of the film.
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The three main steps in producing a radiograph are
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Exposure, developing, and fixation
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Any of the body tissues may be injured by excessive exposure to X or gamma rays but particularly sensitive are:
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Blood, Lens of the eyes, Internal organs
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Failure to properly fix the radiographic film results in?
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Film that will not have a long shelf life and will brown making it unable to read again.
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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:
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To protect the film from backscatter.
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By definition a film that has wide latitude also has
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low contrast.
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When a lead foil is scratched, a resulting radiograph would show:
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Defined dark lines corresponding to the scratches
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Root passes made using the submerged arc welding process requires the use of metal backing or a backing bar.
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True
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Which welding method uses a weld wire electrode that contains a flux that is inside?
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FCAW
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is an area where a portion of the root pass has been blown out of, or through the root pass of the weld.
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Burn Thru
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is a groove burnt into the base metal and left unfilled.
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under cut
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Oxides, fluxes, or non-metallic inclusions that are trapped in the weld metal or between weld and base metal is called:
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Slag
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occurs when gasses in the molten weld metal do not escape to the atmosphere before solidification of the weld metal.
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Porosity
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An elongated gas pocket that tunnels down the center of the root pass and follows the direction of welding is called
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hollow bead
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When the root pass inside surface on a stainless steel weld does not have adequate protection from the atmosphere (shielding or backing), the result is an off colored, powdery and irregular root surface which is called:
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Oxides
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Radiographs of electronic circuit boards should be made using what type of radiation source.
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X-ray
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