Physics Course/Types of Waves/Sound Waves

Sound Wave

Sound wave is a Longitudinal Wave. When Sound Wave travels through air it will create expanding or shrinking column of airs called Rarefraction and RareExpansion.

Sound Wave | || | ||

Sound Wave Characteristics

1. Sound does not exist in vacuum .
2. Sound wave requires medium of matter to spread itself . Sound wave travels through any medium Solid , Liquid , Gas
3. The speed of Sound wave varies with Pressure and Temperature of the medium . Sound wave travels at a speed v = λ f . At Standard Pressure & Temperature in air the speed is calculated equal to v = 333 m/s
4. Sound Wave that is audible to human ear is in the frequency range 20Hz - 20KHz .

Sound's Effects

When Sound wave travel through a medium if there is a blocking object that has a height greater than the wavelength of sound wave . Sound wave will suffer from the following effects

Reflection

Sound wave being reflected back to the medium it comes from and can create interference with other wave in the medium

Refraction

Only part of Sound wave is passing through . Sound does not reach its destination

Diffraction

Wave travels through narrow opens

Interference

When two sound waves travel toward each other will interfere either Constructively or Destructively to produce different sound interferences like Noise, Echoe, Intermittent, No sound

Applications

Tele Communication

In Tele Communication, in order to carry Sound wave over a long distance sound wave must be mixed with a high frequency carrier wave in a process called Modulation .

In Radio Communication, There are 3 modulations methods are used in mixing Sound wave and Carrier wave namely AM - Amplitude Modulation, FM - Frequency Modulation, PM - Phase Modulation.

In analog electronics , AM and FM is widely used . In digital electronic, PM is used

Reference

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