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Introduction |
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We hear various kinds of sound in our daily life, pleasant sounds called the musical sounds, unpleasant sound called the noise, loud sound, high pitched sound etc. |
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Sound as a Wave |
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Sound is the form of energy propagated as waves which our ears receive. |
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Propagation of Sound |
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A wave motion, in which the particles of the medium oscillate about their mean positions in the direction of propagation of the wave, is called longitudinal wave. |
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Sound Needs a Medium to Travel |
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Sound can propagate not only through gases but also through solids and liquids. Some materials like air, water, iron etc can easily transmit sound energy from one place to another. |
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Basic Terms Connected to Waves |
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As wavelength is the distance covered during one oscillation and frequency is the number of oscillations per second, the product of the wavelength and frequency would give us the wave velocity. |
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Speed of Sound |
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The speed of sound depends on the properties of the medium through which it travels. |
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Reflection of Sound |
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According to the law of reflection of sound the directions in which the sound is incident and reflected make equal angles with the normal to the reflecting surface and the three lie in the same plane. |
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Echoes |
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Sound waves suffer reflection from the large obstacles. As a result of reflection of sound wave from a large obstacle, the sound is heard which is named as an echo. |
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Reverberation |
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Due to reflection of light a sound created in a big hall will persist until it is reduced to a value where it is no longer audible. |
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Practical Applications of Reflection of Sound |
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Bats and dolphins can detect the presence of an obstacle by hearing the echo of the sound produced by them. This process is called sound ranging. |
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Range of Hearing |
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The sound waves having frequencies less than the audible range are called infrasonic waves. |
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Applications of Ultrasound |
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It is used for medical diagnosis and therapy and also as a surgical tool.Bats and porpoises use ultrasound for navigation and to locate food in darkness. |
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SONAR |
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One of the most important applications of the reflection of sound is oceanographic studies. For this purpose, we use a system called the SONAR. The SONAR is abbreviated form of Sound Navigation and Ranging. |
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Echolocation |
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Echolocation is a method of sensory perception by which certain animals orient themselves to their surroundings, detect obstacles, communicate with others and find food. |
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Structure of Human Ear |
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Ears are extremely sensitive device with the help of which we are able to hear. |
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Question and Answers |
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Multiple Choice Questions |
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