write about reflection of sound and what are the uses of multiple reflection of sound
Answers
Reflection of Sound
Sound wave also gets reflected as light waves do. Bouncing back of sound wave from the surface of solid or liquid is called reflection of sound.
Reflection of sound follows the Laws of Reflection as light wave does. This means the angle of incident wave and reflected wave to the normal are equal.
For reflection of sound a polished or rough and big obstacle is necessary.
Loudspeaker, Megaphone, bulb horn:
Loudspeaker, Megaphone and bulb horn are devices used to send the sound in desired direction without spreading the sound all around. These devices act on the laws of reflection of sound wave.
In such devices, a funnel like cone shaped tube is used. Sound is introduced at the narrower end of tube and let to come out from wider end. Because of successive reflections, the amplitude of sound is added up which makes the sound louder. The name ‘Loudspeaker’ is given as it is used to make the sound louder.
Stethoscope:
Stethoscope is used to hear the sounds of internal organs of a patient; for diagnostic purposes. It works on the laws of reflection of sound.
Soundboard
Sound board is used to send the sound towards audience in big hall or auditorium. This works on the basis of laws of reflection of sound waves.
Sound board is a big concave board and is set in such a fashion behind the stage that speaker is at the focus. Sound coming from speaker falls over sound board and gets reflected towards the audience. As a result, the audience sitting in the hall even at far distance from the speaker can clearly hear what the speaker is saying.
Additionally, the ceiling of the auditorium is also made curved so that it also acts like sound board. The curved surface of the ceiling reflects the sound waves and facilitates better hearing.
Echo:
The sound which we hear after reflection is called echo or echo of sound. One can hear the echo by shouting loudly in a big hall. After shouting loudly, the same sound reaches the ears after reflecting from the surface of the wall. Echo of sound can be heard by producing sound at place surrounded by hills or big buildings.
Thus, repetition of sound because of multiple reflection of sound wave is called echo
