Sound waves

Introduction

Sounds are waves generated through compression and expansion of any medium that is solid, liquid or gas into certain frequencies. To human ear sound is defined as 20 to 20000Hz. Waves above 20000Hz are called ultrasound and below 20Hz are called infrasoundinfra-sound.

Sound waves are called longitudial longitudinal mechanical waves since the medium contents oscillate in the direction of wave propagation.

Image Added

Figure 1. Longitudinal wave (http://www.acs.psu.edu/drussell/demos/waves/wavemotion.html)

Sound wave has its own intensity which is defined by common word sound level. Sound intensity is gotten by following pattern:

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