Chapter 4, Problem 8P

Ultrasonic waves have frequencies too high to be detected by the human ear, but they can be produced and detected by vibrating crystals. Calculate the wavelength of an ultrasonic wave of frequency $\text{5}.0\times \text{1}{0}^{\text{4}}{\text{s}}^{-\text{1}}$ that is propagating through a sample of water at a speed of $\text{1}.\text{5}\times \text{1}{0}^{\text{3}}{\text{m s}}^{-\text{1}}$ . Explain why ultrasound can be used to probe the size and position of the fetus inside the mother’s abdomen. Could audible sound with a frequency of $\text{8}000{\text{ s}}^{-\text{1}}$ be used for this purpose?