Physics: Chapter 12 - Electromagnetic Waves

12.1 Electromagnetic Waves
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Radio Waves - Longer wavelength Lower Frequency
Microwaves
Infrared
Visible light
Ultraviolet
X-rays

Gamma rays - Shorter wavelength High Frequency

Properties of electromagnetic waves

1. Electromagnetic waves are transverse waves.
2. They transfer energy from one place to another.
3. They can travel through vacuum. Do not require any medium to travel around.
4. They travel at a speed of 3.0 X 10⁸ ms^-1 in vacuum.
5. They obey the laws of reflection and refraction.
6. They carry no electric charge.
7. Their frequencies do not change when they travel from one medium to another. Only their speeds and wavelengths change from one medium to another.
   

12.3 Uses of Electromagnetic Waves
Application of elctromagnetic waves
Gamma Rays: Radiation therapy (Cancer treatment)
X-Rays: Medical and everyday application
Ultraviolet: Sunbeds and sterilisation of medical equipment
Visible light: Optical fibres
Infrared: Remote controllers and ear thermometers
Microwaves: Ovens and satellites
Radio waves: Radio and telecommunications

Effects of Electromagnetic Waves
Infrared heating - Skin absorbs infrared waves, making us feel warm.