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SAI INTERNATIONAL SCHOOL
                                                          Class8
                                                     Lesson Notes
                                                   Subject-Physics
                                                       CH-Sound
                                         Subtopic- Propagation of sound




               Propagation of sound
                          1. Sound needs a medium to propagate (eg: air, liquid, solid).
                          2. Sound cannot travel through Vacuum.
                          3. As sound needs medium to propagate it is a mechanical wave.
                          4. Sound propagates as longitudinal wave in air.
                          5. The speed of sound is maximum in solids, of middle order in liquids and
                              least in gases.
                          6. Speed of sound depends on
                                 a. Density of medium: as density increases speed increases.
                                 b. Humidity of air: as humidity increase speed increases.
                                 c. Temperature of air: as temperature increases speed increases.
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