reflection, refraction and diffraction
Tuesday, February 27, 2007
What Is The Difference Between Ascot And Cravat
1.4 reflection, refraction and diffraction
l wave properties as manifested through a series of phenomena that constitute the essence of wave behavior. So the waves bounce against a barrier, change direction when moving from one medium to another, adding their effects in a very special and can overcome obstacles or skirting the edges of an object.
When a wave reaches the surface separating two different media are produced in general, two waves, one propagating in the same medium as the incident wave, so that the projection of velocity on the surface normal is opposite to the corresponding incident and reflected wave is called, and the other half goes to the other and is called refrectada or transmitted wave.
incident wave energy is distributed between the reflected wave and transmitted, as shown in the figure no.1.
For reflection:
acoustic reflection law establishes the angle of reflection is exactly equal to the angle of incidence.
Reflection:
Definition: The reflection of sound on a surface returning to the limiting environment. When a sound wave is a large surface area compared to its wavelength, undergoes a reflection.
The wave may follow the same direction with that permission, but in the opposite direction or can change direction after hitting the surface.
The reflections of sound waves from a source A, result in a reverse spherical wave whose source is a source of "image" secondary mirror at the same distance. The intensity of the sound image is the same as the original sound source
- If the dimensions the object are small compared to the wavelength of sound shaping, the reflected sound wave will be insignificant.
- The phenomenon of reflection gives rise to the study and analysis of reflections that arise:
The Echo, Reverb, and standing waves.
reflection on the wall explains the phenomenon of Eco
If the distance to the wall is enough (and they are parallel), you can hear the very voice reflected because the time it takes sound to travel to and allows you to separate the perception of the incident wave reflected.
Refraction:
Definition: Occurs when changing media. Because of this change of medium, the speed of sound varies and this variation causes a change of direction from the incident wave.
Definition: The change of direction that a sound wave suffers passing from one medium to another with different characteristics. See figure no.1.
The phenomenon of refraction is a change in the speed of wave propagation, associated with the step change from one medium to another of a different nature or different properties. This change in speed results in a change in the direction of wave motion. As a result the refracted wave is diverted to a angle to the incident.
Example:
The propagation of sound in air undergoes refraction, since its temperature is not uniform. On a sunny day the air layers near the surface are hotter than the high and the speed of sound, which increases with temperature, is higher in the lower layers in the high.
This leads to sound, as a result of refraction, is deflected upward.
The opposite phenomenon occurs during the night because the land cools faster than air.
Diffraction:
is when a wave or waves tend to spread or concentrate at the corner of any obstacle in its path, rather than simply reflected. This process is called diffraction and shadow.
Definition: The property that has surround sound barriers or spread for the space through an opening where the wave fronts pass, they become broadcasting centers in the points that are intercepted by the obstacle.
Diffraction takes place basically at low frequencies and MEDIDIA gradually decreases the frequency increases.
Examples:
The narrower the aperture, GREATER DEGREE OF DIFFRACTION
Subscribe to:
Post Comments (Atom)
0 comments:
Post a Comment