Question

_____________ can be put on the specimen in the form of magnetic powder.

(a) Uranium

(b) Black iron oxide

(c) Charred wood

(d) Chromium

I have been asked this question by my school principal while I was bunking the class.

The question is from Testing Aircraft Materials topic in division Testing Aircraft Materials of Aerospace Materials & Processes

Answer 1

The correct choice is (b) Black iron oxide

To elaborate: It is necessary to put a substance on the specimen that can indicate the presence of flaws on it. Black iron oxide or ferroso ferric oxide is generally used as magnetic powder. They can be applied either wet or dry.