When the frequency is lower in ultrasound imaging, what is the effect on the wavelength?

When the frequency of an ultrasound wave decreases, the wavelength increases. This relationship is derived from the fundamental equation that relates wave speed, frequency, and wavelength:

[ \text{Wave Speed} = \text{Frequency} \times \text{Wavelength} ]

In ultrasound imaging, the speed of sound in soft tissue is relatively constant. Therefore, if the frequency of the ultrasound wave lowers, and the speed of sound remains the same, the wavelength must increase to maintain the equality in the equation.

Lower frequencies produce longer wavelengths, which can impact imaging characteristics such as resolution and penetration in medical ultrasound. Lower frequencies allow for deeper tissue penetration but may sacrifice resolution because the longer wavelengths do not create as detailed images as higher frequency waves do. Understanding this relationship is crucial for selecting appropriate frequencies based on the imaging requirements in ophthalmic sonography or other ultrasound applications.