The maximum thickness for Ir-192 is closest to which value?

The maximum thickness for Ir-192 is closest to which value?

• A. 3.5 inches
• B. 2.5 inches
• C. 4.0 inches
• D. 5.0 inches

Answer: (A)

In industrial radiography, how far the gamma rays can penetrate a metal like steel determines the maximum thickness you can image in a single exposure. Ir-192 emits gamma radiation with enough energy to penetrate moderate thicknesses, so you typically can inspect welds up to about three to four inches of steel with practical exposure times. Among the given options, the value near three and a half inches best matches this common practical limit, making it the closest match. If the material were thicker, a higher-energy source such as cobalt-60 or a longer exposure might be needed, which is why a thicker option like five inches isn’t used as the practical maximum for Ir-192.

In industrial radiography, how far the gamma rays can penetrate a metal like steel determines the maximum thickness you can image in a single exposure. Ir-192 emits gamma radiation with enough energy to penetrate moderate thicknesses, so you typically can inspect welds up to about three to four inches of steel with practical exposure times. Among the given options, the value near three and a half inches best matches this common practical limit, making it the closest match. If the material were thicker, a higher-energy source such as cobalt-60 or a longer exposure might be needed, which is why a thicker option like five inches isn’t used as the practical maximum for Ir-192.