Working: Sonar consists of transmitter and a detector and is installed in a boat or a ship as shown in Fig. The transmitter produces and transmits ultrasonic waves. These waves travel through water and after striking the object on the seabed, get reflected back and are sensed by the detector.
The detector converts the ultrasonic waves into electrical signals which are appropriately interpreted. The distance of the object that reflected the soundwave can be calculated by knowing the speed of sound in water and the time interval between transmission and reception of the ultrasound. Let the time interval between
transmission and reception of ultrasound signal be t and the speed of sound through sea water be v. The total distance, 2d travelled by the ultrasound is then, 2d = vxt.
Applications: The sonar technique is used to determine the depth of the sea and to locate underwater hills, valleys, submarine, icebergs, sunkenship etc.
