What is the velocity of sound in water as used in immersion testing data?

• A. 6.32 cm/s
• B. 1.49 x 10^5 cm/s
• C. 6.32 x 10^5 cm/s
• D. 1.00 x 10^3 cm/s

Answer: (B)

In immersion testing data, the speed of sound in the coupling water is the value used to translate time into distance. Water carries ultrasonic waves at about 1,490 meters per second, which is 1.49 x 10^5 centimeters per second. This is the standard reference speed because the pulse travels through water on its way to the reflector and back, so distance to the reflector is half of (speed in water × time). The options with speeds far from this range (too slow like a few cm/s, or too fast like hundreds of thousands of cm/s) don’t match how sound propagates in water. Therefore, the correct value is approximately 1.49 x 10^5 cm/s.