Summary of chapter Sound?
Answers
Explanation:
Sound waves are longitudinal waves
The frequency of a sound is an indication of how high or low the pitch of the sound is.
The human ear can hear frequencies from 20 to \(\text{20 000}\) \(\text{Hz}\). Infrasound waves have frequencies lower than \(\text{20}\) \(\text{Hz}\). Ultrasound waves have frequencies higher than \(\text{20 000}\) \(\text{Hz}\).
The amplitude of a sound determines its loudness or volume.
The tone is a measure of the quality of a sound wave.
The speed of sound in air is around \(\text{340}\) \(\text{m·s$^{-1}$}\). It is dependent on the temperature, height above sea level and the phase of the medium through which it is travelling.
Sound travels faster when the medium is hot.
Sound travels faster in a solid than a liquid and faster in a liquid than in a gas.
Sound travels faster at sea level where the air pressure is higher.
The intensity of a sound is the energy transmitted over a certain area. Intensity is a measure of frequency.
Ultrasound can be used to form pictures of things we cannot see, like unborn babies or tumours.
Echolocation is used by animals such as dolphins and bats to “see” their surroundings by using ultrasound.
Ships use sonar to determine how deep the ocean is or to locate shoals of fish.
Answer:
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Explanation:
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.