Explain the working and application of a sonar.

The acronym SONAR stands for Sound Navigation and Ranging.

Sonar is a device that uses ultrasonic waves to measure the distance, direction and speed of underwater objects.

Principle: It uses the phenomenon of echoes in determining the sea-depth and locating the presence of under-water objects.

Working: 

i) Sonar consists of a transmitter and a detector and is installed in a boat or a ship.

ii) The transmitter produces and transmits strong ultrasonic waves.

iii) These waves travel through the water and after striking the object the beam is reflected from the seabed and is received by an under-water detector which is also mounted on the ship.

iv) The detector converts the ultrasonic waves into electrical signals which are appropriately interpreted.

v) The time interval between transmission and reception of the ultrasonic signal is noted. 

The SONAR method is also called echo ranging. This technique is used to determine the depth of the sea and to locate underwater hills, valleys, submarine, icebergs, sunken ship etc.