Module 02
The Electromagnetic Spectrum
Visible light is a tiny window in a much wider range of waves. Each travels at 3 × 10⁸ m/s in vacuum. Click a band to inspect it.
← shorter wavelength · higher frequencylonger wavelength · lower frequency →
Visible Light
400 nm – 700 nm · 4.3 × 10¹⁴ – 7.5 × 10¹⁴ Hz
Discovered byIsaac Newton (spectrum, 1666)
SourceSun, incandescent & LED lamps
DetectionHuman eye, photodiodes, CCD/CMOS sensors
Applications
- Vision
- Photography
- Optical communication
Common Properties
- • Need no material medium — propagate through vacuum.
- • Same speed c = 3 × 10⁸ m/s in vacuum.
- • Transverse, not deflected by electric or magnetic fields.
- • Obey reflection & refraction; frequency unchanged when entering another medium.