EM Waves and the Electromagnetic Spectrum

Study Notes

Electromagnetic radiation, or EM waves, differs from nuclear radiation as it is pure energy rather than particles.
It can be envisioned as waves of electric and magnetic fields or as packets of energy called photons.
Electromagnetic radiation propagates through space at the speed of light, defined as a wave carrying energy.

EM radiation includes seven types: radio waves, microwaves, infrared light, visible light, ultraviolet light, X-rays, and gamma rays.
Human eyes can detect only visible light, while some animals, like snakes and birds, perceive infrared and ultraviolet light, respectively.

The electromagnetic spectrum encompasses the range of all EM radiation types, characterized by varying frequencies, wavelengths, and intensities.

Electromagnetic waves consist of oscillations in electric and magnetic fields, illustrating the interrelationship between electricity and magnetism.
Changes in the electromagnetic field generate these waves, with frequency related to the speed of oscillation and wavelength.
Unlike mechanical waves, electromagnetic waves travel at the speed of light without needing a medium.

Radio Waves: Low frequency and long wavelength (above 1 mm); used in communication (e.g., radios, cell phones).
Microwaves: Higher frequency (300 MHz to 10 THz) and shorter wavelength (1 mm to 25 micrometers); utilized in microwave ovens, radar, and Wi-Fi.
Infrared Light: Wavelengths between 25 micrometers and 2.5 micrometers; frequencies between 10 THz and 400 THz; produced by heat sources.
Visible Light: Detected by the human eye; wavelengths between 400 and 750 nanometers; frequencies from 400 THz to 750 THz.
Ultraviolet Light: Wavelengths from 1 to 400 nanometers; frequencies range from 1 THz to 1000 THz; can cause skin damage and cancer.
X-Rays: High-energy form with dangerous potential; wavelengths from 1 nm to 1 pm; crucial for medical imaging.
Gamma Rays: Highest frequency, smallest wavelength (< 1 pm); extremely dangerous yet valuable in medical diagnostics and cancer treatment.

Harmless EM Waves: Radio waves, microwaves, infrared light, and visible light are generally safe for humans due to their lower frequencies.
Harmful EM Waves: Ultraviolet light, X-rays, and gamma rays can cause cell damage, cancer, and pose health risks.
Nuclear Concerns: Gamma rays contribute to the dangers of nuclear waste, which can emit harmful radiation for extensive periods post-production.