Which of the following frequencies would probably result in the greatest attenuation losses?

• A. 1 MHz
• B. 2.25 MHz
• C. 5 MHz
• D. 10 MHz

Answer: (D)

Attenuation in ultrasonic testing increases with frequency because higher‑frequency waves interact more with the material—more scattering and absorption occur, so more energy is lost as they travel. That means the signal decays faster with distance at higher frequencies, reducing penetration depth. Among the options, the highest frequency experiences the most attenuation, so 10 MHz would have the greatest losses. This also shows the common trade‑off: higher frequency gives better resolution but shorter travel distance due to attenuation.