Electromagnetic Waves and Their Properties

Electromagnetic Waves

• Electromagnetic waves are electric and magnetic waves produced by vibrating electric charges.
• They transfer energy through a vacuum without needing a medium.
• Energy transfer is between electric and magnetic fields, existing independently of matter.
• All electromagnetic waves travel at 300,000,000 m/s in a vacuum.
• Speed decreases when traveling through matter.
• Electromagnetic waves can act as both waves and particles (photons).

Waves vs. Particles

• A wave is a disturbance carrying energy.
• A particle is a piece of matter.
• Photons are massless bundles of energy.

Electromagnetic Spectrum

• Electromagnetic radiation is energy given off by electromagnetic waves.
• The electromagnetic spectrum covers all frequencies of this radiation.
  • Longer wavelength = lower frequency = lower energy
  • Shorter wavelength = higher frequency = higher energy

Types of Electromagnetic Waves

Radio Waves

• Emitted by radio stations, MRI's, RADAR, Wi-Fi, TV, and cell phones.
• Longest wavelength, lowest frequency.

Microwaves

• Used for cooking, Doppler radar, and GPS.

Infrared Waves

• Used in night vision goggles, remote controls, and infrared photography.

Visible Light

• The only electromagnetic waves humans see.
• Emitted by the sun and light bulbs.
• Different colors correspond to different wavelengths.
  • Red has the longest, violet the shortest (ROYGBIV).

Ultraviolet Waves

• Emitted by the sun.
• Used in light bulbs, killing bacteria, and vitamin D production.

X-Rays

• Used for detecting bone breaks and fractures (e.g., X-rays, CAT scans).
• Small enough to penetrate skin cells.
• Overexposure can cause cancer.

Gamma Rays

• Used to kill cancer cells, sterilize equipment, and radioactive tracers.
• Smallest wavelength, highest frequency.