Patterns that move through everything.
Waves & Optics
From ripples on a pond to laser light, waves carry energy without carrying matter. Optics studies how light reflects, refracts, and interferes.
Chapter outline
Lessons in this chapter
Short, focused lessons. Each one ends with a worked example and a quick quiz.
Key concepts at a glance
The essential ideas, paired with their equations.
Wave Equation
01Wave speed equals frequency times wavelength.
Snell's Law
02How light bends when crossing materials of different optical density.
Doppler Effect
03Why a passing siren shifts pitch — motion compresses or stretches waves.
Interference
04Overlapping waves add — sometimes amplifying, sometimes cancelling.
Diffraction
05Waves bend around obstacles and through slits, revealing their wave nature.
Polarization
06Restricting the plane in which a transverse wave oscillates.
Frequently asked
What is the difference between transverse and longitudinal waves?+
Transverse waves oscillate perpendicular to their motion (light); longitudinal waves oscillate along it (sound).
Why does light bend in water?+
Light slows down in denser media, refracting toward the normal — described by Snell's law.