5. A boat is using an ultrasound based echo-sounder to map the surface of the seabed. This ultrasound device uses a frequency of 45kHz. a) What is the wavelength of this ultrasound in water? b) If in one location the sound wave takes 0.03s to be detected by the boat and in a second it takes 0.07s to be detected, what is the difference in the depth of the sea bed at these two locations