9.1 Sound Waves: Pressure Amplitude
9.2 Characteristics of Sound
9.3 Doppler’s Effect
Important Short Questions and Answers in Short
Q1. What is pressure amplitude?
👉 Maximum variation in pressure due to sound wave.
Q2. Define intensity of sound.
👉 the amount of sound energy passing through a specific area per unit of time, typically measured in watts per square meter (W/m²)
Q4. What is loudness?
👉 Perceived intensity by ear; depends on I and frequency.
Q5. What is pitch?
👉 Perceived frequency of sound; higher f → higher pitch.
Q6. What is quality (timbre)?
👉 Difference in tone for same pitch & loudness; depends on harmonics.
Q7. State Doppler effect.
👉 Apparent change in frequency due to motion of source or observer.
✅ Formula Sheet (Quick Revision)
Numerical Examples
Example 1: Pressure amplitude
Example 2: Doppler effect (moving source)
Example 3: Intensity relation with pressure amplitude
