Electromagnetic Spectrum

Electromagnetic Spectrum

1. Main Features of the Electromagnetic Spectrum

   • GAMMA RADIATION
     • USE: Killing Cancer cells
       • Shortest Wavelength and highest frequency
   • X-RAYS
     • USE: Medical pictures/scans of bones
   • ULTRAVIOLET RADIATION
     • USE: Sunbeds
   • VISIBLE LIGHT
     • USE: Sight/Seeing
   • INFRA-RED
     • USE: Optical fibre communication
   • MICROWAVES
     • USE: Heating up food/cooking
   • RADIO WAVES
     • USE: Television Signals
       • Longest Wavelength and lowest frquency

2. Radio and Television Communications

   • Radio waves are produced as a result of accelerating electrons within a circuit.

3. All Electromagnetic waves:

   • Can travel in a vacuum.
   • travel at the speed of light in a vacuum – 3 x 108 ms-1
   • Are transverse waves.

4. Satellite television and telephones

   • Radar allows ships and planes to detect remote objects using microwave radiation.
   • Many forms of wireless also rely on microwaves to communicate between one and another, although not at a level which can cause thermal heating.
   • Lastly, microwaves are used in the aptly named microwave oven to heat food.

5. Electrical appliances, remote controllers for televisions and intruder alarms

   • Infrared waves is commonly associated with thermal radiation.
   • A vast majority of hot objects emit IR radiation, including ourselves, hot pieces of coal, heaters, and the sun.
   • modern military and security often employ equipment capable of detecting IR radiation (Thermal goggles etc.) as a means to spot humans within a difficult to see environment.

6. Medicine and security

   • X-rays are also produced in x-ray tubes by firing electrons at a high velocity and having them rapidly decelerate as they collide with a metal anode (usually tungsten), giving off x-rays in the process
   • X-rays are very penetrating and thus have important uses, especially in the field of medicine.
   • x-rays are used in x-ray machines to provide images of our body’s internals without the need for surgery
   • They are also used for radiotherapy and the management of cancer.

7. Safety Issues

   • XRAYS
     • XRAYS are more penetrating than microwaves
       • Brief expose to x-rays carry the increased risk of cancer, since x-rays are ionizing
         • x-rays may cause mutations in living cells when they pass through the body, hence it is a very good idea that you limit your exposure to x-rays.
   • MICROWAVES
     • When we microwave water, it gets warmer. The kinetic energy transferred is making the particles of the water vibrate faster, hence its temperature increases
       • If we are exposed to microwaves for a long period of time, there is the danger that permanent damage will be caused to our internal organs as they will warm up when the waves travel through our body.