SOUND

SOUND
Is a form of energy formed by a vibrating body.Sound wave requires requires material medium hence they are mechanical wave.They are also mechanical wave because they set up a train of refraction and compression when it travels through an air medium.It is measured in decibel and it is represented by db

For experiment purposes, musical sound may be made by tunning forks
What's a tunning fork? Is a material which has two hard steel prongs.

Transmission of sound
   Since sound is a mechanical wave it can be transmitted through a material medium such as solid, liquid, gas


Sound can travel through solid

In the olden days the doctor  💉  uses a stethoscope which consist of a thin wooden rods with  broadened ends by placing one end to his ear and applying the other end to the patient's chest, so the doctor will hear the sound of the heart-beats which is transmitted through the wood.

Speed 🚤 of sound

Air 💨 330/340ms-¹
 Liquid 🚰 1500ms-¹     
 Solid     5000ms-¹

Factors that affect the velocity of sound 

Density of the medium
Wind
Temperature


Echoes

Echo is a reflected sound which is heard at 0.1 sec or more after the original sound is being produced.
Let us suppose a person clap 👏  his hands,when standing some distance from a high wall and listen to the echo.The time which elapses before the echo arrives will depend on the distance away 🏃 to the wall.Now,in order that the echo may be heard separately from the original sound (clap) 👏 it must arrive atleast 0.1sec later
Velocity of echo=2x/t

©2018_Physics-helper

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