SONAR stands for SOund Navigation And Ranging. This technique is also known as Echo Ranging.

Working of SONAR

SONAR

SONAR techniques involves a transmitter and receiver. Whole system is placed in ship. Transmitter produces ultrasonic waves or ultrasound . These waves are transmitted to water. Waves travels through water and and strikes to the object under water or seabed. After striking, these waves gets reflected from object or seabed. Thus, these waves are collected by receiver. Later, receiver converts the ultrasonic waves into electrical signal which are examined to understand underwater situations and obstructions. Hence, distance of object from the ships can be determined by knowing the speed of ultrasonic waves in water and time interval between transmission and receiving of ultrasonic waves. By this technique, depth of sea or distance of any object underwater can be calculated using formula

d =(v × t ) / 2

Application of SONAR

SONAR technique is used for determining submarines underwater, to detect underwater objects like sunken ships, etc. This is also helpful in determining the depth of sea.

Similar technique to SONAR is used by bats and porpoises. ultrasonic waves are produced by bats. This sound travels through air and strikes to obstacle or prey. This waves reflects back and is received by the bat. This helps the bat to locate danger or food for them. Ultrasonic waves are used by porpoises for travelling in water and locate food.

Numerical Based on SONAR technique

Question: Ship transmits ultrasonic waves, to bottom of sea. These waves returns to ship after 4 seconds. Speed of ultrasonic waves is 1200 m/s. Find the distance of sea bed from ship.
Solution:
Transmission time = t = 4 s
speed of ultrasonic waves = v = 1200 m/s
Distance travelled by ultrasonic waves is 2 × depth of sea i.e 2d
Therefore, 2d = speed of time × time
= 1200 m/s ×4
2d = 4800 m
d = 4800 / 2
= 2400 m
Therefore, distance of ship from seabed is 2400m.

Watch video on SONAR Technique here

This article is helpful for Class 9 Science

Keywords: SONAR technique, Ultrasonic waves, Working of SONAR, Application of SONAR

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