Question

What is echo?Waht are the necessary conditions for its occurence? What is SONAR?How is it used to determine the depth of an ocean?

Answer 1

ECHO-The sound waves which gets reflected back after hitting any obstacle and reaches the human ear after some

time interval is called an Echo.In order to hear an audible echo the time interval between the reflected sound and original sound must be at least 0.1 s

Necessary conditions for occurence of an echo:-

1>. Time interval=$0.1s$

2>. Speed of sound =$344m/s$

3>. Temperature =${22}^{0}C$

4>. Total distance covered by the sound from the point of generation to the reflecting surface and back should be at least = 34.4 m.

SONAR-The acronym SONAR stands for Sound Navigation And Ranging.It is based on the concept of how dolphins communicate.It is a device which uses ultrasonic waves to measure the distance, direction and speed of underwater objects. This technology is widely used in submarine,ships and boats.

Determination of depth of an ocean by the use of SONAR.

A SONAR consists of a transmitter and a detector, this transmitter produces and transmits ultrasonic waves which travels through water and after hitting the sea bed gets reflected back and is sensed by the detector.The detector converts these ultrasonic waves into electrical signals which are than interpreted. The distance of the object that reflected the sound wave can be calculated by knowing the speed of sound in water and the time interval between transmission and reception of the ultrasound.