Electromagnetic Waves Summary

Electromagnetic Spectrum

Types of Electromagnetic Waves

• Radio waves
• Microwaves
• Infrared radiation
• Visible light
• Ultraviolet radiation
• X-rays
• Gamma radiation

Wave Properties

• Electromagnetic waves are transverse waves.
• Travel at the same speed (300,000,000 m/s).
• Can travel through a vacuum.
• Do not transfer matter.
• Energy depends on wavelength.

Relationships

• Shorter wavelength = higher frequency.
• Energy increases as frequency increases.
• Therefore, as wavelength decreases, energy and frequency increase.

Wave Speed Equation

• v = f \times λ
• v = wave speed in m/s
• f = frequency in Hz
• λ = wavelength in m

Uses and Hazards

• Infrared: Remote controls, optical fibers.
• Microwaves: Satellite TV, mobile phones, heating food.
• Radio waves: Radio/TV broadcasting, communications.
• Microwaves & Radio waves: Can heat internal body parts.
• Infrared radiation: Can cause skin burns.
• Ultraviolet: Detecting counterfeit banknotes, sunbeds
• Gamma rays: Sterilizing equipment, killing cancer cells, can cause cancer

Frequency Units

• Hertz (Hz)
• Kilohertz (kHz) = 1,000 Hz
• Megahertz (MHz) = 1,000,000 Hz