ENTC 402 Radiography correctly answered graded A+ 2023 passed

ENTC 402 Radiography When radiographing to the 2-2T quality level, an ASTM penetrometer for 13 mm (0.5 in.) thick 2024 aluminum alloy has a thickness of - correct answer 25 x 10-5m (10 mils) The penetrating ability of an X-ray beam is governed by: - correct answer kilovoltage The ability to detect a small discontinuity or flaw is called: - correct answer radiographic sensitivity The difference between the densities of two areas of a radiograph is called - correct answer radiographic contrast Lead foil in direct contact with X-ray film: - correct answer intensifies the primary radiation more than the scatter radiation Radiographic sensitivity, in the context of the minimum detectable flaw size, depends on: - correct answer 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 In order to decrease geometric unsharpness - correct answer radiation should proceed from as small a focal spot as other considerations will allow A general rule often employed for determining the kilovoltage to be used when X-raying a part is that - correct answer the kilovoltage should be as low as other factors will permit 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? - correct answer 15 s One of the general rules concerning the application of geometric principles of shadow formation to radiography is - correct answer the distance between the source and the material examined should always be as great as possible 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 - correct answer milliamperage The most common material used to provide protection against X-rays is - correct answer lead A graph showing the relation between material thickness, kilovoltage, and exposure is called - correct answer an exposure chart A graph which expresses the relationship between the logarithm of the exposure applied to a film and the resulting film density is called - correct answer the characteristic curve When producing radiographs, if the kilovoltage is increased, the - correct answer subject contrast decreases The sharpness of the outline in the image of the radiograph is a measure of - correct answer radiographic definition 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)? - correct answer 100 mR/hr