What happens to the wavelength of a longitudinal mode wave when a 5.0 MHz transducer is substituted for a 2.25 MHz transducer?

The wavelength of a longitudinal mode wave is inversely related to its frequency when the speed of sound in the material remains constant. This relationship is described by the formula:

Wavelength = Speed of Sound / Frequency

When a 5.0 MHz transducer is used instead of a 2.25 MHz transducer, the frequency has increased. According to the inverse relationship, when frequency increases, the wavelength must decrease. Therefore, substituting a higher frequency transducer (5.0 MHz) results in a shorter wavelength compared to a lower frequency transducer (2.25 MHz).

This principle is fundamental in understanding ultrasonic testing, as different frequencies can penetrate materials to varying depths and provide insights into different sizes of defects. Higher frequency ultrasound tends to yield shorter wavelengths, which can improve the resolution of the images being produced, helping to identify smaller defects that may not be as distinguishable at lower frequencies.