If the ultrasound was detected after  5 seconds when sent from the river to the bottom of the ocean. If the speed of sound in water is 1600 m/s then what is the depth of the river?

• Ultrasound is a sound with a frequency greater than 20,000 hertz.
• This has a wide range of applications in science and technology.
• This is due to its ability to travel along well-defined paths even when obstacles are present.
• SONAR (Sound Navigation And Ranging) measures distances and other parameters of any object using ultrasonic waves.

Speed of sound $s=1600 \mathrm{m}/\mathrm{s}$

time $t=5 s$

depth  $d=?$

The sound must now travel some distance 2d to reach the ground and return.

Distance = speed $x$ time

$2 \mathrm{d}=1600 \mathrm{m}/\mathrm{s}\times 5 \mathrm{s}=8000 \mathrm{m}$

$\Rightarrow d=4000 \mathrm{m}=4 \mathrm{km}$

Hence, the depth is $4 \mathrm{km}$.