Question

Explain working and application of SONAR.

Answer 1

Hint: It is a technique that uses sound propagation to navigate, communicate with or detect objects on or under the surface of the water, such as other vessels, simply SONAR uses sound waves to see in the water.

Complete step-by-step answer:
Let’s know on which principle SONAR works, that is the principle of reflection (echo) of sound waves from the object.
SONAR stands for Sound Navigation and Ranging.
Working-
As we know that it is for sound navigation and ranging how it actually works let’s see.
If we consider ships to explain this working. This ship consists Transducers and detectors. A beam of ultrasonic sound is produced and transmitted by the transducer of the SONAR. Transducers is a device which is used to produce ultrasonic sound. That ultrasonic sound travels through sea water. After that, echo is produced by the reflection of this ultrasonic sound which is detected and recorded by detector, which is converted into signals. Distance (d) of underwater object calculated by time (t) taken by echo produced from reflection of ultrasonic waves to return with speed (v) given by,
\[2d=v\times t\]
This method of calculating distance is called “echo-ranging”.

Applications-
1. This technique used to measure depth, direction and speed of underwater objects such as submarines and shipwrecks.
2. In the military also, it is useful to detect the presence of enemy ships.
3. Also, it is used in ordinary things like fish finding, depth sounding, mapping of the sea bottom, acoustic location for divers.
4. For cleaning purposes also, SONAR is useful.

Additional Information:
There are two types of technology which made the name SONAR.
 First one that is passive SONAR is essentially listening for the sound made by vessels and another is active sonar is emitting pulses of sound and listening for echoes.
The study of underwater sound is known as underwater acoustics or hydro acoustics.

Note- This technique was first recorded by Leonardo da Vinci in 1490 who used a tube inserted into the water to detect vessels by ear. It was developed during world war 1. In the 19th century, an underwater bell was used as an ancillary to lighthouses or lightships to provide warning of hazards.