The Ultrasonic form of non-destructive examination is done to find?

The Ultrasonic form of non-destructive examination (NDE) is particularly designed to locate and assess sub-surface discontinuities within materials. This technique utilizes high-frequency sound waves that are introduced into the material being tested. When these sound waves encounter an inconsistency such as a crack, void, or inclusion, they reflect back to the transducer, allowing for analysis.

Ultrasonic testing is ideal for detecting sub-surface discontinuities because it can penetrate through the material, which is not achievable with methods focused solely on surface examination. This capability makes ultrasonic testing a valuable tool in ensuring the integrity and safety of structures that may have internal flaws not visible from outside.

While surface discontinuities may be detected using other NDE methods, ultrasonic testing excels at uncovering deeper issues that could lead to material failure if left undetected. Hence, the focus on finding sub-surface discontinuities aligns with the primary function of ultrasonic NDE, marking it as the correct answer for this question.