What is the role of frequency in ultrasonic testing?

In ultrasonic testing, frequency plays a crucial role in determining both the resolution and penetration capabilities of the ultrasonic waves being used. Higher frequencies are associated with better resolution, meaning they can provide a clearer and more detailed image of the internal structure of the material being tested. This increased resolution is particularly valuable when detecting small defects or fine details.

However, one of the trade-offs of using higher frequencies is that they have a reduced penetration ability. This means that while they can give a clearer picture, they might not be able to effectively reach deeper within thicker materials, potentially missing flaws located further below the surface. Conversely, lower frequencies offer greater penetration, allowing them to travel deeper into thick materials, but they sacrifice some level of resolution.

Therefore, the correct answer underscores the balance between resolution and penetration that must be considered when selecting the frequency for ultrasonic testing.