Sound Class 9 Extra Questions

CBSE Notes for Sound Class 9 Extra Questions

A sound is a form of energy which produces a sensation of hearing in our ears. It is produced due to the vibration of different objects. Sound waves are longitudinal waves and propagate in a medium in the form of compressions and rarefactions. These waves cannot travel in a vacuum. A sound wave can be described by its three important properties i.e., frequency, amplitude, and speed. It can be reflected at the surface of a solid or a liquid and follows the laws of reflection, like a light. The repetition of sound caused by the reflection of sound waves by a tall building or a mountain is known as an echo. The time interval between the original sound and reflected one should be at least 0.1 s in order to hear a distinct sound. However, the persistence of sound due to the repeated reflections of sound is known as reverberation. Human beings and most of the animals are able to hear with the help of a sense organ, called the ear. It consists of three basic parts - the outer ear, middle ear, and inner ear. Please refer Sound Class 9 Extra Questions for more information.