Final answer:
The correct frequency range for using guided waves on thicker test objects is C) 10 kHz to 200kHz. This allows for effective penetration without losing resolution, unlike the human audible range which is 20 Hz to 20,000 Hz. For medical scans like ultrasounds, higher frequencies are used for better resolution but have lower penetration depths.
Step-by-step explanation:
The frequency range for using guided waves on thicker test objects is typically C) 10 kHz to 200kHz. This range is most effective as it allows the waves to penetrate the material's thickness without excessive loss of resolution. Using too low a frequency may not provide enough resolution for defect detection, whereas too high a frequency may result in poor penetration and excessive attenuation, making it difficult to detect flaws deep within the object.
As a comparison, the human range of hearing is generally acknowledged to be from 20 Hz to 20,000 Hz, which is quite different from the frequency range utilized in testing materials using guided waves. Moreover, the greater the frequency of the ultrasound used for probing, the higher the resolution of detail but the lower the penetration depth. For example, an abdominal ultrasound scan may typically use a 7 MHz frequency, which falls well within the higher end of the guided waves frequency range for thick materials.