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Electromagnetic spectrum e learning


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Electromagnetic spectrum e learning

  2. 2. Objectives  Describe the 7 main components of the electromagnetic spectrum  State the properties of electromagnetic waves (EM wave)  State the applications of electromagnetic waves
  3. 3. What are Electromagnetic waves?  Consist of 7 components  Radio waves  Microwaves  Infra-red radiation  Visible light  Ultra-violet waves  X-rays  Gamma rays 105 m 10-14 m Wavelength Rich Men In Vegas Use X-ray Goggles
  4. 4. How is electromagnetic waves form?  Created by accelerating electric charges, moving the charges back and forth  Produce oscillating magnetic and electric field
  5. 5. Electromagnetic Waves  Electromagnetic spectrum is continuous.  No distinct boundaries between each component.  Gamma rays have the shortest wavelength and highest frequency.  Radio waves have the longest wavelength and lowest frequency.
  6. 6. Properties of Electromagnetic waves  Transfer energy from one place to another  They are transverse waves  Travel through vacuum with the speed of light (3 x 108 m s-1)  Show wave properties like reflection and refraction  Obey wave equation v = fλ
  7. 7. Application of Electromagnetic waves Radio waves (10-1 to 105)  Longest wavelengths  Able to go around obstructions due to their long wavelength  Used in radio broadcasting, telephone transmission, television, radar, navigation system
  8. 8. Microwaves (10-3 to 10-1)  Microwave oven – cause the water molecules in the food to vibrate. The vibration causes friction at a molecular level which will heat up the food.  Satellite communication and television – signals are transmitted through aerial dishes to satellites in the space. Application of Electromagnetic waves
  9. 9. Infra-red Radiation (10-7 to 10-3)  All object emit infra-red radiation  We experience infrared-radiation in the form of heat  Ear thermometer: measure the amount of infra- red radiation that emanates from the eardrum.  Used in remote controls for electronic devices and infra-red motion detectors. Application of Electromagnetic waves
  10. 10. Visible Light (10-7)  Only part of the EM spectrum that can be detected by human eye.  Wavelength: 700nm (red) to 400nm (violet)  Laser can be used in industries to weld metals together and in medicine.  Optical fibres in telecommunications Application of Electromagnetic waves
  11. 11. Application of Electromagnetic waves Ultra-Violet (UV) Radiation (10-8 to 10-7)  Sunlight is the main source of UV radiation  Ultraviolet lamps are used in sunbeds for artificial tanning.  Used in hospital for sterilisation - kill bacteria and viruses
  12. 12. Application of Electromagnetic waves X-Rays (10-13 to 10-8)  used to produce the X-ray images to examine a person’s body or tooth decay  used in X-ray scanners in airports  can penetrate through all materials except lead.
  13. 13. Application of Electromagnetic waves Gamma Rays (10-14 to 10-10)  It can be used to treat cancer by killing cancer cells.  Cause serious damages to living tissues.