1. WHAT?
1.1. Non-physical waves that do not require a medium to travel
2. Properties
2.1. All the components travel at the speed of light in a vacuum
2.2. All components obey law of reflection and refraction
2.3. All components transfer energy
2.4. All components are transverse waves
2.5. All components obey wave equation
3. Gamma Rays
3.1. Emitted by the nucleus of radioactive nucleus
3.2. Applications:
3.2.1. Sterilize medical instruments
3.2.2. Kill cancerous cells
3.3. DANGER!
3.3.1. Gamma rays can seriously damage living cells
4. X-Rays
4.1. Produced by firing high-speed electrons at a metal target and the sudden loss in speed produces x-rays
4.2. Application:
4.2.1. Used to create an image of the bone structure
4.3. DANGER!
4.3.1. Excessive exposure to x-rays can cause considerable damage to living cells
5. Ultra-violet (UV) rays
5.1. Produced by the sun
5.2. Application:
5.2.1. Tans the human skin
5.2.2. Kills bacteria
5.3. DANGER!
5.3.1. Excessive exposure to UV rays can cause skin cancer
6. Visible EM Waves
6.1. Application:
6.1.1. Used by all living creatures to see
7. Infra-red Rays
7.1. Emitted by hot objects
7.2. Application:
7.2.1. An infra-red detector will convert the infrared image into a visible one
7.3. Example:
7.3.1. Night-vision goggles
7.3.1.1. Enhances the image
7.3.1.1.1. Amplifies the tiny amount of lights that are present but cannot be seen by the naked eye
7.3.1.2. Thermal imaging
7.3.1.2.1. Captures upper portion of light spectrum which is emitted as heat from objects
8. Microwaves
8.1. Produced by special electronic devices
8.2. Application:
8.2.1. Used to heat up food
8.2.1.1. Done by giving energy to the water molecules present in food which in turn heats the food up
8.2.2. Used in satellite communications
9. Radiowaves
9.1. Produced by electrons oscillating in electric circuits
9.2. Application:
9.2.1. Used in television and radio transmission
10. Effect of absorbing EM waves on cells and tissues
10.1. High frequency EM waves
10.1.1. Example:
10.1.1.1. Gamma Rays
10.1.1.2. X-Rays
10.1.2. Ionisation of cells
10.1.2.1. Knocks off electrons and produces ions which causes damage to cells and tissues
10.2. Low frequency EM waves
10.2.1. Example
10.2.1.1. Light
10.2.1.2. Microwaves
10.2.2. Heating effect on cells