Question

Which of the following holds true for gamma-ray radiography as compared to x-ray radiography?

(a) Better detection of castings of uniform thickness

(b) Better for detection of small defects

(c) More rapid method

(d) Used for thick castings

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This question is from Metal Composition Testing, Inspection of Materials in division Testing of Materials, Foundry & Powder Metallurgy of Engineering Material & Metallurgy

Answer 1

Correct choice is (d) Used for thick castings

Easy explanation: Gamma-rays are used for detecting small defects in casting sections less than 50 mm as well as castings thicker than those in x-rays. Gamma-rays are better for examination of varying thickness due to less scatter. X-ray is a much quicker method requiring seconds or minutes, whereas gamma-ray method requires hours.