Explain the working and applications of sonar.
SONAR stands for sound navigation and ranging . SONAR is a device which is used by ships and submarines to locate position of other vessels in the ocean. These are of two types. One is passive, which only detects the incoming. Another one is active SONAR which transmits sound pulses and detects the reflected echoes to detect presence of other sea vessels.
Principle behind SONAR is reflection of sound.
The sound sent is reflected back from the sea bed which is known as echo.
Let the depth of the ocean be D
For perpendicular focusing of the sonar
V = 2D/t
=>D = Vt/2
Where V = speed of sound in water
t = time after the echo is detected.
Thus, depth of the ocean is evaluated.
Sonar is a very useful technique which can help determine what lies beneath the ship, boat or a submarine. It has been used to discover shipwrecks, lost treasures, sunken features etc.
It is also used in military for detecting the presence of enemy ships .