Question

write a short note on SONAR

Answer 1

SONAR is a device for determining water depth and locating underwater objects like reefs submarines and school of fishes.
To find the depth of an ocean a strong ultrasonic wave is sent from the ship towards the bottom of ocean.
On striking the bottom of the ocean the ultrasonic wave is reflected upwards towards the ship.This wave is recieved by a suitable receiver.The time of travel from the source of sound to the reciever is noted.We can calculate the depth of ocean floor if the velocity of sound in water is known:
Depth of ocean floor=( Vel. of sound in sea water × Time ) /2

Answer 2

Sonar (sound navigation and ranging)

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

The transmitter produces and transmit ultrasonic waves.These waves travel through water and after striking the objects on seabed,get reflected back and are sensed by the detector.The detector converts ultrasonic waves into electrical signals which are interpreted. The time taken for the echo to return to ship is measured by sonar apparatus.The distance of underwater object is then calculated from time taken by echo to return.The time it takes for an echo to return is used to find out how far away something is.

2d=v*t

d=distance from ship to the bed of the sea

v=speed of sound through seawater

t=time interval between transmission and reception of ultrasound signal.