9. Nature and speed of the sound wave

  

1. The echo-receiver of a sonar attached to a ship receives the echo from the bottom of the sea 3 seconds after the ultrasonic waves were sent into the sea.
If the speed of sound in water is 1440 \(m/s\), what is the depth of the sea? 21601062 \(m)

  

2. The speed of sound in a solid is __________ than in airgreaterlesser.