ARDMS Ultrasound Physics & Instrumentation Practice Exam

As frequency increases, which of the following occurs to wavelength?

1. Wavelength increases

2. Wavelength decreases

3. Wavelength remains constant

4. Wavelength becomes negligible

The correct answer is: Wavelength decreases

As frequency increases, the wavelength of a wave decreases. This relationship is defined by the equation that connects wavelength, frequency, and the speed of sound (or light) in a given medium: \[ \text{Speed} = \text{Frequency} \times \text{Wavelength} \] In this equation, if the speed of the wave remains constant (as is typically the case for sound in a specific medium), an increase in frequency will necessitate a decrease in wavelength to maintain the equality. This principle is fundamental in understanding wave behavior, especially in acoustics and ultrasound physics. Therefore, when considering ultrasound and its applications, higher frequency waves yield shorter wavelengths, which can lead to better resolution in imaging; this is one of the reasons high-frequency transducers are used when fine detail is required.