PhysicsChapter 11: Electromagnetic Waves
Visible
Introduction
Visible light is the small part of the electromagnetic spectrum that can be detected by the human eye. Its approximate wavelength range is around: 400 nm to 700 nm The exact limits vary with definition and human sensitivity.
Definition
Colour and Wavelength
Approximate order from longer to shorter wavelength: Red → Orange → Yellow → Green → Blue → Violet Red has longer wavelength and lower frequency. Violet has shorter wavelength and higher frequency.
Uses
Visible light is used in: vision; photography; optical communication; microscopes; telescopes; lighting.
White Light
White light contains a range of visible wavelengths. A prism can separate these wavelengths through dispersion.
Exam preparation
Exam Focus
Quick revision
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Review the key facts, formulas and checks before you move on.Visible
Sticky Notes · Quick Revision
VISIBLE
- Human eye detects
60-second revision
- Visible ≈ 400–700 nm.
- Red → long λ.
- Violet → short λ.
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