LESSON 02
Wave Behavior
Reflection, refraction, diffraction & interference.
Frequency1.00×
Amplitude1.00×
When waves meet boundaries or each other, they do interesting things. These four behaviours explain echoes, rainbows, hearing around corners and noise-cancelling headphones.
Reflection
Waves bounce off a barrier. Angle of incidence equals angle of reflection.
Refraction
Waves change speed (and direction) when entering a new medium — this is why a straw looks bent in water.
Diffraction
Waves spread out when passing through a gap or around an edge. The smaller the gap, the more spreading.
Interference
Two waves overlap. Crests + crests → constructive (louder/brighter). Crest + trough → destructive (quieter/dimmer).
Key Formulas
Law of reflection
θᵢ = θᵣ
angles measured from the normal
Real-life applications
- Noise-cancelling headphones
- Lenses and eyeglasses
- Radar and sonar
Summary
- Four behaviours: reflect, refract, diffract, interfere.
- Interference can add or cancel waves.
Check Yourself
Q1.Bending of waves around a corner is called…
Q2.Two identical waves meet crest-to-crest. The result is…