---
id:"kb-2026-00373"
title:"Electromagnetic Spectrum"
schema_type:"TechArticle"
category:"science"
language:"en"
confidence:"high"
last_verified:"2026-05-22"
generation_method:"ai_assisted"
ai_models:["claude-opus"]
derived_from_human_seed:true
primary_sources:
  - title:"Introduction to Electrodynamics (4th Ed, Griffiths)"
    type:"book"
    year:2017
    url:"https://www.cambridge.org/highereducation/books/introduction-to-electrodynamics/3EDC2A247A70E2F72D685535D315EB68"
    institution:"Cambridge University Press"
secondary_sources:
  - title: "MDN Web Docs — HTTP"
    type: "documentation"
    year: 2026
    url: "https://developer.mozilla.org/en-US/docs/Web/HTTP"
    institution: "Mozilla"
completeness: 0.88
ai_citations:
  last_citation_check:"2026-05-22"
---

## TL;DR

The electromagnetic spectrum encompasses all types of EM radiation, ordered by wavelength/frequency: radio (longest), microwave, infrared, visible light (400-700nm), ultraviolet, X-ray, gamma ray (shortest). All travel at speed of light (c = 299,792,458 m/s). Maxwell's equations (1865) unified electricity, magnetism, and light.

## Core Explanation

Radio waves: communication, broadcasting. Microwaves: radar, cooking, WiFi. Infrared: heat, night vision. Visible: ROYGBIV (red 700nm → violet 400nm). UV: sunburn, vitamin D, sterilization. X-rays: medical imaging, security. Gamma rays: nuclear processes, cancer treatment, most energetic. Photon energy: E = hf (Planck). Higher frequency = higher energy = more penetrating/damaging.

## Further Reading

- [Introduction to Electrodynamics (4th Ed, Griffiths)](https://www.cambridge.org/highereducation/books/introduction-to-electrodynamics/3EDC2A247A70E2F72D685535D315EB68)