Write short notes on reflection of sound waves from plane and curved surfaces. Reflection of sound through the plane surface

Explanation

Sound reflects from a harder flat surface, is called as specular reflection.
Specular reflection is observed only when the wavelength of the source is smaller than dimensions of the reflecting surface, as well as smaller than surface irregularities.
When the sound waves hit the plane wall, they bounce off in manner similar to that of light. Suppose a loudspeaker is kept at an angle with respect to a wall (plane surface), then the waves coming from the source (assumed to be a point source) can be treated as spherical wave front). Therefore, the reflected wave front on the plane surface is also spherical, such that its centre of curvature (which lies on the other side of plane surface) can be treated as the image of the sound source (virtual or imaginary loud speaker) which can be assumed to be at a position behind the plane surface.

Reflection of sound through the curved surface
The behaviour of sound is different when it is reflected from different surfaces-convex or concave or plane The sound reflected from a convex surface is spread out and so it is easily attenuated and weakened. Whereas, if it is reflected from the concave surface it will converge at a point and this can be easily amplified. The parabolic reflector (curved reflector) which is used to focus the sound precisely to a point is used in designing the parabolic mics which are known as directional microphones. We know that any surface (smooth or rough) can absorb sound.