Dolphins of the open ocean are classified as Type II Odontocetes (toothed whales). These animals use ultrasonic "clicks" with a frequency of 55 kHz to navigate and find prey. (a) Suppose a dolphin sends out a series of clicks that are reflected back from the bottom of the ocean 75 m below. How much time elapses before the dolphin hears the echoes of the clicks? (The speed of sound in seawater is approximately 1530 m/s.) (b) What is the wavelength of a 55-kHz sound in the ocean?
The sound wave must travel back and forth (twice the depth).
Calculate the time by dividing the distance by the speed of sound.
Now use the formula