Physics for IGCSE & O level - Waves And Sounds (Section 5 - No. 1)
If ultrasound pulses take 0.03 s to travel from the boat to the seabed and return, how deep is the water under the boat, assuming the speed of sound in water is 1400 m/s?
21 m
42 m
84 m
126 m
설명
The depth is half the distance travelled: 1/2 * (1400 m/s * 0.03 s) = 21 m