#### Could you give me the formula for figuring the wavelength of an ultrasound wave? — BH

The wavelength of any wave is equal to the speed of that wave divided by its frequency. In air, the speed of sound is about 330 meters per second, so an ultrasonic wave with a frequency of 50,000 cycles per second would have a wavelength of about 6.6 millimeters. Since sound travels much faster in liquids or solids, the wavelengths would be larger than in air.