Physics for IGCSE & O level - Waves And Sounds (Section 5 - No. 5)
If a pulse of ultrasound takes 0.1 s to travel to the sea-bed and return, and the speed of sound in water is 1400 m/s, what is the depth of the water?
140 m
70 m
14 m
7 m
설명
The depth is half the distance travelled: 1/2 * (1400 m/s * 0.1 s) = 70 m