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 4 seconds after the ultrasonic waves were sent into the sea.
If the speed of sound in water is 1520 \(m/s\), what is the depth of the sea? 10813040 \(m)

  

2. The time period of a wave is reciprocal of__________FrequencyAmplitude.