Question

X-rays can be used to inspect materials of steel up to a thickness of __________ inches.

(a) 3

(b) 15

(c) 0.3

(d) 26

The question was posed to me in an international level competition.

The origin of the question is Testing Aircraft Materials topic in chapter Testing Aircraft Materials of Aerospace Materials & Processes

Answer 1

Correct answer is (a) 3

The best I can explain: X-rays can be used to inspect materials made up of steel sufficiently up to a thickness of three inches. If the material being inspected is not as dense as steel, it can also be tested for a higher thickness value.