Sound & Acoustics
- 2 subtopics
- Standard
3.1 Reflection of sound and echoes
An echo is the sound heard after reflection from a distant obstacle, after the original sound has stopped. To hear a distinct echo, the reflecting surface must be at least about 17 metres away at normal room temperature.
3.2 Resonance and forced vibrations
Resonance is a special case of forced vibration. It happens when the frequency of an external periodic force matches the natural frequency of the body, causing oscillations of large amplitude.