Electromagnetic Spectrum Overview

The Electromagnetic Spectrum

  • Definition: White light passed through a slit and prism produces a continuous spectrum (ROYGBIV).
  • Wavelength Range: Visible light: 400-750 nm; Electromagnetic spectrum: $10^{-16} m$ to $10^{6} m$.

Key Regions of the Spectrum

  • Shorter wavelengths = higher energy and frequency.
  • Types of radiation in increasing wavelength and decreasing energy:
    • Gamma rays (highest energy)
    • X-rays
    • Ultraviolet (UV)
    • Visible light (ROYGBIV)
    • Infrared (IR)
    • Microwaves
    • Radio waves (lowest energy)

Energy and Interaction

  • Visible Light:
    • Not enough energy to break most chemical bonds; processes of color perception involve absorption of specific wavelengths.
    • Violet has the highest energy in visible light.
  • Ultraviolet Light:
    • Higher energy than visible light, can damage DNA, cause sunburns.
  • X-rays:
    • Higher energy than UV, cumulative health risks can lead to cancer.
  • Gamma Rays:
    • Extremely high energy; exposure can be deadly; sources include radioactive decay and cosmic radiation.
  • Infrared Light:
    • Causes molecular vibrations, felt as heat.
  • Microwave Radiation:
    • Interacts with water molecules; increases molecular kinetic energy, heats food by agitation, not by direct heating.
  • Radio Frequency Radiation:
    • Used in AM/FM broadcasts, cell phones; safe diagnostic MRI utilizes low-energy.

Summary

  • Spectrum: Ranges from radio waves (least energy) to gamma rays (most energy).
  • Each type of radiation has unique interaction characteristics with matter and varying health implications.