Non-Destructive Testing (NDT) Practice Test

What part of the sound beam should ultrasonic inspections be performed?

1. Near Field

2. Far Field

3. Both Near and Far Field

4. None of the Above

The correct answer is: Far Field

Ultrasonic inspections are most effectively performed in the far field of the sound beam. In this region, the sound waves have spread out sufficiently and have developed a more uniform beam profile, allowing for more accurate measurement and detection of flaws within the material being inspected. The far field is where the intensity of the ultrasound becomes stable and the beam, which is initially highly directional, starts to become more collimated. In the far field, the reflections from discontinuities within the material are more discernible, resulting in clearer signals that can be interpreted for defect characterization. This makes it easier to analyze and assess material integrity. While the near field contains a lot of information, it is often less reliable due to the varying intensity and dispersion of the sound waves, which can complicate flaw detection. Therefore, performing inspections primarily in the far field ensures more consistent and accurate results, making it the preferred option for nondestructive testing.