Describe with the help of a diagram, how compression's and rarefaction's are produced in air near a source of sound.  


Compressions and Rarefactions - Teachoo.png


When an object vibrates, it forces the particles of medium around it to also vibrate

  • As the object moves forward , it pushes and compresses the air in front of it creating a region of high pressure. This region is called a compression.
  • As the object moves backward , it creates a region of low pressure. This region is called a rarefaction.
  • As the object vibrates (moves backward and forward), a series of compression and rarefaction is created in the air. 

These make the sound waves propagate through the medium

  1. Class 9
  2. Chapter 12 Class 9 - Sound

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CA Maninder Singh is a Chartered Accountant for the past 9 years and a teacher from the past 16 years. He teaches Spoken English, Written English, Grammar and Vocabulary at Englishtan.