Page 46 - WAVES

Sonar

• SONAR (Sound Navigation And Ranging) used to

locate underwater objects or to measure the depth of a
seabed. ship
• The ultrasonic waves (sound waves frequency>

20,000 Hz) used in this technique.
• The ultrasonic waves emitted from the transmitter and

reflected by objects on the seabed. Then reflected
waves detected by the receiver.
• Time interval, t between emission and reception of the

ultrasonic wave signal measured using electronic Receiver Transmitter
devices.

• If the speed of the sound waves, v is known, the depth
of the seabed, d can be measured by using the
formula: seabed

vt d = depth of seabed
d= v = speed of sound wave in water

2 t = time interval

CRO used to determine the time
interval, t

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