Electromagnetic Waves
by Luqmanul Haziq Kamarudin
1. Applications
1.1. Radiowaves: radio comminication
1.2. microwave: oven
1.3. infrared: intruder alarm
1.4. visible light: telecommunications
1.5. ultraviolet: sun beds
1.6. x rays: radiological apps
1.7. gamma rays: medical treatment
2. Effects
2.1. Heating
2.1.1. when water absorbs microwaves (as in ovens), they are warmed up.
2.1.2. The burning of coal gives out infrared radiation as heat to surrounding
2.2. Ionisation
2.2.1. UV rays are highly energetic
2.2.1.1. able to ionise atoms which are harmful to living tissue
2.2.1.2. excessive exposure can lead to sunburn and skin cancer
2.3. Damage to living cells and tissue
2.3.1. Gamma rays are ionizing radiation
2.3.2. They are used to treat tumour cells. However, they are able to damage the surrounding cells and tissues which absorb the rays
3. Properties
3.1. Transfer energy from wave source
3.2. Classified as TRANSVERSE WAVES
3.3. Speed of: 3 x 10^8 m/s in vacuum
3.3.1. In vacuum
3.3.1.1. no medium required
3.3.1.2. travel in straight lines
3.4. Frequency in Hertz (Hz)
3.5. Wavelength in metres (m)
4. Electromagnetic Spectrum
4.1. each wave has it's own frequency and wavelength
4.2. when arranged from lowest frequency to highest, em spectrum is obtained
4.2.1. high frequency = high energy content = short wavelength