The law of reflection of sound waves states that the angle of incidence is always equal to the angle of reflection. But unlike reflection of light on a highly smooth surface, in the reflection of the sound wave, a part of the incident wave gets transmitted to the medium where it hits. This wave that gets absorbed or transmitted to the medium is called a transmitted wave.
The section of the reflected sound waves from hard surfaces and therefore the reflection of string waves from their ends determines whether or not the interference of the reflected and incident waves can be constructive or destructive. For string waves at the ends of strings, there's a reversal of section and it plays a vital role in manufacturing resonance in strings. The reflected wave and the incident wave get imposed to each other while moving in opposite directions, the mechanism of propagation is gone, and the resulting vibration is called a standing wave.
The sound intensity close to a tough surface is increased as a result of the reflected wave adding to the incident wave, giving a pressure amplitude that's double to the thin "pressure zone" near the surface. This is employed in the pressure zone microphones to extend sensitivity. The doubling of pressure provides a six-unit (6 decibels) increase within the signal picked up by the electro-acoustic transducer.
Reflection of a light wave is either reflective (mirror-like) or diffusive (retaining the energy, however losing the image) depending on the character of the surface it falls.
Considering the reflection of light on a very smooth reflecting surface, the laws of reflection can be stated as follows: