Reflection of sound
Sound bounces off a surface of solid or a liquid medium like a rubber ball that bounces off from a wall. An obstacle of large size which may be polished or rough is needed for the reflection of sound waves. The laws of reflection are:
· The angle in which the sound is incident is equal to the angle in which sound is reflected.
· Direction of incident sound, direction of the reflected sound and the normal are in the same plane.
Megaphones, loud speakers, horns, musical instruments such as nathaswaram, shehnai and trumpets are all designed to send sound in a particular direction without spreading it in all directions. In these instruments, a tube followed by a conical opening reflects sound successively to guide most of the sound waves from the source in the forward direction towards the audience.
Stethoscope is a medical instrument used for listening to sounds produced in the body. In stethoscopes these sounds reach doctor’s ears by multiple reflections that happen in the connecting tube.