sound

1. 
Presented by
athira j nair

3. Soundisavibrationthatpropagatesasa
typicallyaudiblemechanicalwaveof
pressureanddisplacement,througha
mediumsuchasairorwater.

4. 
Thetoandfroorbackandforthmotionofan
objectiscalledvibration.Someinstruments
producesoundduetothevibrationof
membranes,someduetothevibrationofstrings,
andsomeothersproducesoundduetothe
vibrationofanaircolumn.

5. 
Soundcanpropagatethroughcompressible
mediasuchasair,waterandsolidsas
longitudinalwaves

6. CharacteristicsofSound
Asoundcanbecharacterizedbythefollowing
threequantities:
(i)Pitch.
(ii)Quality.
(iii)Loudness.

7. Pitchisthefrequencyofasoundas
perceivedbyhumanear.Ahighfrequency
givesrisetoahighpitchnoteandalow
frequencyproducesalowpitchnote..

8. 
Apuretoneisthesoundofonlyonefrequency,
suchasthatgivenbyatuningforkorelectronic
signalgenerator.
Thefundamentalnotehasthegreatestamplitude
andisheardpredominantlybecauseithasa
largerintensity.Theotherfrequenciessuchas
2fo,3fo,4fo,.............arecalledovertonesor
harmonicsandtheydeterminethequalityofthe
sound.

9. 
Loudnessisaphysiologicalsensation.It
dependsmainlyonsoundpressurebutalso
onthespectrumoftheharmonicsandthe
physicalduration.

10. 
Themaximumdisplacementofavibrating
particlefromitsmeanorequilibriumpositionis
calleditsamplitude.
Timeperiod
Thetimetakenbythevibratingparticleforone
fullvibrationoroscillationiscalledthetime
periodofvibration.
Frequency
Thenumberofvibrationspersecondiscalledthe

11. AUDIBLE SOUND
Not all sound produced by vibrating bodies is
audible. The human ear can recognise the sounds
of frequencies in the range of 20 Hz to 20,000 Hz.
This range of frequency of sound is called audible
sound.
Some animals like dogs and snakes can hear
sounds of frequencies greater than 20,000 Hz.

12. 
Infrasonicsounds
Soundsoffrequencieslessthan20Hzare
calledinfrasonicsounds.
Ultrasonicsounds
Thesoundsoffrequenciesgreaterthan
20,000HzarecalledUltrasonicsounds.