If the distance to a reflector doubles, what happens to the time between pulse transmission and echo detection?

When considering the relationship between distance to a reflector and the time required for an ultrasound pulse to travel to that reflector and back, one must understand the basic principles of sound travel. Sound travels to the reflector and then returns to the transducer, effectively requiring two trips through the same distance.

If the distance to a reflector doubles, the round trip distance (the sound traveling to the reflector and back) also doubles. Since the time taken to travel a certain distance is directly proportional to that distance, if the distance is doubled, the time required for this round trip will also double.

Therefore, if the distance to the reflector increases, the time taken for the pulse to travel to the reflector and back will correspondingly increase, confirming that when the distance doubles, the time also doubles.