PowerPoint Presentation

MYSELF - SARTHAK KENJALE CLASS – 8F MY TOPIC IS AUDIBLE AND INAUDIBLE SOUNDS.

Audible and Inaudible Sounds. We know that we need a vibrating body for the production of sound. Can we hear the sound of all vibrating bodies? The fact is that sounds of frequencies less than about 20 vibrations per second (20 Hz) cannot be detected by the human ear. Such sounds are called inaudible. On the higher side, sounds of frequencies higher than about 20,000 vibrations per second (20 kHz) are also not audible to the human ear. Thus, for human ear, the range of audible frequencies is roughly from 20 to 20,000 Hz..

Whenever an object virbrates , sound is produced. For example , when a simple pendulum vibrates sound is produced. But the sound produced by a vibrating simple pendulum is not heard by us. This is because the frequency of vibration of a simple pendulum is very low. It may be 2 or 3 heartz only.

And our ears can't hear sounds of such low frequencies. Our ear can hear sounds 20Hz to 20,000hz frequency only. Sounds which are produced in this frequency are called audible sounds. If the sound is above 20kHz or below 20 hz so it is known to be Inaudible sound. From this example we conclude that all the vibrating objects do not produce audible sounds..

Some animals can hear sounds of frequencies higher than 20,000 Hz. Dogs have this ability. The police use high frequency whistles which dogs can hear but humans cannot. The ultrasound equipment, familiar to us for investigating and tracking many medical problems, works at frequencies higher than 20,000 Hz..

Differentiate between audible and inaudible sounds..

Answer- (20-20,000 Hz). Human can hear sound in the range of (a) 200-2000 Hz (b) 20-20,000 Hz (c) 2-20000 Hz (d) 2000-200000 Hz.

Answer Yes, animals can hear sounds of frequencies higher than 20,000 Hz For Example - dogs.

Inaudible sounds are those sounds who have frequency not audible for human ear. Their frequency is above 20KH.

THANK YOU.