Question

class 9 sound chapter easy notes

Answer 1

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⭐️⭐️Here, you will get the CBSE Class 9 Science, Sound: Chapter notes (Part-I). These chapter notes are prepared by the subject experts and cover every important topic from the chapter. You get a crisp and brief explanation of all these topics so as to make your learning easy and organized. At the end of the notes you can try the questions asked from the discussed set of topics. These questions will help you to track your preparation level and get a hold on the subject.

❤️Main topics covered in this part of CBSE Class 9 Science, Sound: Chapter Notes, are:❤️

✔️Sound-Production and Propagation
✔️Medium
✔️Wave and its Types
✔️Characteristics of Sound
✔️Audible Frequency
✔️Reflection of Sound and its Laws
✔️Applications of Reflection of Sound
✔️Key notes for Chapter - Sound, are:

❤️Sound❤️

Sound is a form of energy which produces a sensation of hearing in our ears.

❤️Production of Sound ❤️

❤️Sound is produced due to the vibration of objects. Vibration is a periodic back-and-forth motion of the particles of an elastic body or mediumkind about a central position. It is also named as oscillation.
For example:

❤️Stretched strings of a guitar vibrate to produce sound. When membrane of a table is struck, it vibrates to produce sound.
Propagation of Sound

❤️The travelling of sound is called propagation of sound.

❤️Sound is propagated by the to and fro motion of particles of the medium.
When an object vibrates, the particles around the medium vibrate. The particle in contact with the vibrating object is first displaced from its equilibrium position. Each particle disturbs the other particle in contact. Thus, the disturbance is carried from the source to the listener.

❤️Only the disturbance produced by the vibrating body travels through the medium but the particles do not move forward themselves.

✨Medium✨

The matter or substance through which sound is transmitted is called a medium.
A medium is necessary for the propagation of sound waves.
The medium can be solid, liquid or gas.
Sound cannot travel in vacuum.
Wave that requires medium to propagate is called Mechanical wave.

✨Wave✨

Wave is a phenomenon or disturbance in which energy is transferred from one point to another without any direct contact between them. For example: Heat, light and sound is considered as a wave.

✨Types of Waves✨

(i) Longitudinal waves

(ii) Transverse waves

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