Round-Trip Time Gives Depth - Biophysical Ultrasound: Echo Timing and Acoustic Interfaces Step by Step

An echo depth is half the sound-speed-times-time path. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.

highlighted = computed this step

Echo time measures an out-and-back path

The pulse travels at 4 meters per second for 6 seconds, so the checked path is 24 meters.

c t=4\cdot 6=24\ \text{m}

Depth is half of the round trip

The reflector depth is half of 24 meters, so the accepted depth is 12 meters.

d=\frac{24}{2}=12\ \text{m}