Sound and Wave Motion
PART-A Unit-I: General Science
Previous Year Questions (PYQ) for this topic
Every TNPSC question asked from this topic, compiled as a PDF. · PDF 2.6 MB
Acoustics - Important Notes - PYQ Points
1. Sound Intensity and Units
- Decibel (dB): A unit used to measure sound intensity.
- Auditory Sensitivity: The primary reason for expressing the unit of a sound amplifier in decibels is the human ear’s sensitivity to sound.
2. Speed and Propagation of Sound
- Effect of Medium: Sound travels fastest in solids. In particular, sound propagates at a very high speed in steel.
- Adiabatic Process: The propagation of sound through a medium was considered an adiabatic process by Laplace (without heat exchange).
3. Types of Sound
| Type | Description |
|---|---|
| Audible Range | From 20 Hz to 20,000 Hz. |
| Infrasonic | Mechanical waves with frequencies below the audible range (less than 20 Hz). |
4. Electronics & Signals
- Television Broadcasting: In television transmission, the sound signal is modulated using Frequency Modulation (FM).
- Amplifier and Oscillator: Conditions required for an amplifier to function as an oscillator:
1. The amplifier must have positive feedback.
2. According
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