# state the laws of reflection of sound .explain three application based on these laws.

The bouncing back of sound when it strikes a hard surface is called reflection of sound. the laws of reflection of sound is same as the refledction of light.

1. The incident sound wave, the reflected sound wave and the normal at the point of incidence, all lie in the same plane.
2. The angle of reflection of sound is always equal to the angles of incidence of sound
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1. The incident sound wave, the reflected sound wave and the normal at the point of incidence, all lie in the same plane.
2. The angle of reflection of sound is always equal to the angles of incidence of sound
it is used for dectecting flaws in metal blocks in industry
it is used in electrocardiography.
it is used to clean hard to reach parts
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A light ray is a stream of light with the smallest possible cross-sectional area. (Rays are theoretical constructs.) The incident ray is defined as a ray approaching a surface. The point of incidence is where the incident ray strikes a surface. The normal is a construction line drawn perpendicular to the surface at the point of incidence. The reflected ray is the portion of the incident ray that leaves the surface at the point of incidence. The angle of incidence is the angle between the incident ray and the normal. The angle of reflection is the angle between the normal and the reflected ray.

The Laws of reflection:

- The angle of incidence is equal to the angle of reflection
- The incident ray, the normal, and the reflected ray are coplanar

Specular reflection (regular reflection) occurs when incident parallel rays are also reflected parallel from a smooth surface. If the surface is rough (on a microscopic level), parallel incident rays are no longer parallel when reflected. This results in diffuse reflection (irregular reflection). The laws of reflection apply to diffuse reflection. The irregular surface can be considered to be made up of a large number of small planar reflecting surfaces positioned at slightly different angles. Indirect (or diffuse) lighting produces soft shadows. It produces less eye strain than harsher, direct lighting.

The applet below illustrates how reflection and refraction takes place in common substances such as water, vacuum, air, glass, and even diamond.

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The following two laws of reflection of light are applicable to sound waves as well:

• The incident wave, the normal to the reflecting surface and the reflected wave at the point of incidence lie in the same plane.
• The angle of incidence i is equal to the angle of reflectionr.
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