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ES, , Sound Class 9th Science, , Topics in the Chapter, , ¢ Introduction, , * Production of Sound, , + Propogation of Sound, , * Sound waves as Longitudinal waves, * Characteristics of Sound wave, , * Wavelength, , * Frequency, , * Time Period, , ¢ Amplitude, , — Pitch, , ~ Loudness, , ~ Quality or Timbre, , * Velocity, , * Speed of sound in various medium, * Sonic Boom, , * Reflection of Sound, , * Echo, , * Reverberation, , * Range of Hearing, * Hearing Aid, , ¢ Application of Ultrasound, , * SONAR

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* Application of Ultrasound, * SONAR, , +« Structure of Human Ear, , ~ Working of Human Ear, , Introduction, , ~ The sensation felt by our ears is called, sound., , ~ Sound is a form of energy which makes, us hear., , ~ Law of conservation of energy is also, applicable to sound., , ~ Sound travels in form of wave., Production of Sound, ~ Sound is produced when object, , vibrates or sound is produced by vibrati, objects.

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Production of Sound, , ~ Sound is produced when object, vibrates or sound is produced by vibrating, objects., , ~ The energy required to make an object, vibrate and produce sound is provided by, some outside source (like our hand, wind, , etc.)., € AS es SS

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~ Example: Sound of our voice is, produced by vibration of two vocal cords, in our throat., , Open vocal chord

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« Sound of a drum or tabla is produced by, , vibration of its membrane, when struck., , , , ~ In laboratory experiments, sound is, produced by vibrating tuning fork. The, vibrations of tuning fork can be shown by, touching a small suspended pith ball (cork, ball) with a prong of the sounding tuning, fork. The pith ball is pushed away with a, great force.