1. Production and Propagation
Sound is produced by vibrating objects and travels as a mechanical wave through a
medium (solid, liquid, or gas). It cannot travel through a vacuum.
2. Characteristics of Sound Waves
- Frequency (ν): Number of oscillations per second. Unit: Hertz
(Hz).
- Amplitude (A): Maximum displacement of particles. It determines
loudness.
- Speed (v): Distance traveled per unit time. v = λν (wavelength ×
frequency).
3. Reflection of Sound
Sound follows the same laws of reflection as light. Phenomena include:
- Echo: Reflection of sound from a distant obstacle.
- Reverberation: Persistence of sound due to multiple reflections.
4. Range of Hearing
- Audible Range: 20 Hz to 20,000 Hz.
- Infrasonic: Below 20 Hz.
- Ultrasonic: Above 20,000 Hz (Used in Ultrasound, SONAR).