An ultrasonic signal with a frequency of 30 kHz returned after being reflected

An ultrasonic signal with a frequency of 30 kHz returned after being reflected from the seabed at a depth of 150 m in 0.2 s. What is the ultrasonic wavelength?

Initial data: ν (frequency of the ultrasonic signal) = 30 kHz = 30 * 103 Hz; h (sea depth) = 150 m; t (time of signal movement to the bottom of the sea and back) = 0.2 s.

1) Determine the travel time of the ultrasonic signal to the bottom of the sea: t1 = t / 2 = 0.2 / 2 = 0.1 s.

2) Let’s calculate the speed of the ultrasonic signal: V = h / t1 = 150 / 0.1 = 1500 m / s.

3) Calculate the length of the ultrasonic wave: λ = V / ν = 1500 / (30 * 103) = 0.05 m = 50 mm.

Answer: The ultrasonic wavelength is 50 millimeters.