Characterizing Wave Phenomena

📋 Course Outline

1. Sound Intensity and Attenuation
2. Diffraction Conditions and Measurement
3. Constructive and Destructive Interferences
4. Young’s Double-Slit Interference
5. Doppler Effect and Frequency Shift
6. Redshift in Astronomy

📖 1. Sound Intensity and Attenuation

🔑 Key Concepts & Definitions

• Sound intensity : the energy transported by a sound wave per unit time and per unit area, expressed in watts per square metre (W·m⁻²)

📝 Essential Points

📐 Formula — The sound intensity level is $L = 10\log\left(\frac{I}{I_0}\right)$ and is expressed in decibels (dB).

• The audibility threshold is $I_0 = 1.0 \times 10^{-12}\ \mathrm{W\,m^{-2}}$, whereas the pain threshold is 1 W·m⁻².

📌 Geometric attenuation occurs when increasing distance spreads the same power over larger spheres, whereas absorption attenuation occurs when a material between the source and receiver reduces the sound intensity.

💡 Memory Hook

Geometric attenuation depends on distance, whereas absorption depends on an intervening material.

📖 2. Diffraction Conditions and Measurement

🔑 Key Concepts & Definitions