Source-to-object distance, object-to-film distance, and source size are the three factors that control the of the radiograph.

Related MCQs

• A good Cobalt-60 shot is made on a 7.6 cm (3 inches) steel casting using an exposure time of 10 minutes and a source-to-film distance of 91.5 (36 inches). If it is necessary to change the source-to-film distance to 61 cm (24 inches), what exposure time would produce a similar radiograph if all other conditions remain the same?
• The range of the specimen thickness that can be adequately recorded on a radiograph is known as the of the radiograph.
• The ‘multi-film’ technique may be used when one radiograph film does not have enough to produce a satisfactory radiograph of a specimen.
• A radiographic exposure with 3700 GBq (100 Ci) source of Ir-192 using source to film distance of 60 cm results in a radiation intensity of 0.12 Gy/h (11.8 R/h) and a radiographic density of 2.5. The intensity of radiation needed to obtain the same density when the source to film distance is changed to120 cm is:
• Which of the following is the correct formula to use for calculating geometric unsharpness if F=source size, T=specimen thickness, D=source to object distance and Ug=geometric unsharpness:
• The approximate radiographic equivalence factors for steel and copper at 220 kV are 1.0 and 1.4 respectively. If it is desirable to radiograph a 1.27 cm (0.5 inch) piece of copper, what thickness of steel would require about the same exposure characteristics?
• If an exposure time of 60 seconds and source to film distance of 365.7 m (1200 feet) 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 457.2 m (1500 feet)?
• A 7.6 cm (3 inches) thick test specimen is radiographed with a source having size of 1.3 cm (1/2 inch), the film is placed in contact with the test specimen. The source to film distance is 40.6 cm (16 inches).The geometric unsharpness obtained is:
• Contrast and definition are the two major factors that determine the of the radiograph:
• Which type of gamma ray source would be used to radiograph a weld in 150 mm thick steel plate?