Wavelength is true about what statement?

• A. It is determined solely by the source
• B. It is determined by both the source and the medium and is not adjustable
• C. It is determined solely by the medium
• D. It is adjustable and only determined by the transducer

Answer: (B)

Wavelength in ultrasound is set by the relationship lambda = c / f, where c is the speed of sound in the medium and f is the transmitted frequency from the source. The speed c depends on the medium (soft tissue, bone, etc.), while the frequency f is determined by the transducer (the source) that’s emitting the wave. Because wavelength depends on both factors, it isn’t controlled by just the source or just the medium alone. In a given setup, the wavelength is fixed by the combination of the chosen transducer and the surrounding medium, and you’d change it only by changing either the transducer frequency or the medium. This is why the statement that wavelength is determined by both the source and the medium—and is not determined by a single factor—best captures the concept.