science

• Compare the relative wavelengths of the different forms of electromagnetic (EM) waves
• Cite examples of practical applications of the different regions of EM waves
• Explain the effects on living things and the environment of EM radiation
• Electromagnetic Spectrum


  The arrangement of different types of radiation
• Electro-


  Electric Field
• Magnet-


  Magnetic Field
• • ic


  With quality of
• Spectrum


  Arrangement or order
• Electromagnetic Spectrum is the arrangement of different types of radiation
• Radiation


  Electromagnetic Waves
• Radiation is a transverse wave because its electric field and magnetic field are 90 degrees from the direction of wave movement
• Radiation is also known as EM wave but different from mechanical wave like sound wave that travels through materials. Radiation travels through space. They travel faster than sound at the speed of 3x10^8m/s inside a vacuum
• Radiation's ability to penetrate materials vary depending on its type which is characterized by corresponding amount of possessed energy
• Wavelength (lambda, λ)


  The distance between two consecutive crests or between two consecutive troughs. Its unit is usually in nanometer (nm)
• Frequency (f; varies)


  The number of cycles per unit time. Cycle is the completion of up-down pattern in a wave having a crest and a trough. Its unit is usually in Hertz (Hz) which means cycles per second
• Energy (E; varies)


  The capacity to do work. Its unit is usually in Joules (J) which means kgm2/s2
• Radiations in EMS are arranged based on wavelength, frequency and energy
• Wavelength and frequency are inversely proportional
• Wavelength and energy are inversely proportional
• Frequency and energy are directly proportional
• Inversely proportional


  As one goes up, the other goes down. As one goes down, the other goes up
• Directly proportional


  As one goes up, the other goes up as well. As one goes down, the other goes down as well
• Radio waves are produced by electric circuit that produces an oscillating electric current in the gap of two conductors serving as transmitter
• Microwaves are produced by oscillator cavities or vacuum tubes called magnetron/klystron
• Infrared rays are produced by vibration and rotation of molecules
• Visible light is produced by excitation and de-excitation of electrons of atoms
• UV rays are produced by very hot objects and large energy level transition
• 1. rays are produced by stopping high energy electron beams by heavy metal
• Gamma rays are produced by radioactive decay and nuclear processes
• Applications of radio waves

  • Radio communication
  • Amplitude modulation, AM (540kHz to 1.6MHz bandwidth)
  • Frequency modulation, FM (88-108MHz bandwidth)
  • Television (TV) broadcasting (54-890MHz bandwidth)
• Radio stations and TV stations send specific frequency in the air. When you change your radio station or TV station, it means your device is changing the frequency it receives
• Applications of radio waves


  • Radio telescope – receives radio signals from distant place like stars which may not be visible through optical telescope
  • Radar – radio detection and ranging
• Applications of microwaves


  • Kitchen: Microwave oven – heats up the water molecules of food
  • Wireless communication beyond radio waves' capability
  • Cell phone
  • Navigational system of ships and aircrafts
  • Satellite communication systems
• Applications of microwaves


  • Weather (Doppler) radar (around 3GHz)
  • Big Bang theory evidence – microwave background radiation
• Weather (Doppler) radar (around 3GHz)
• Big Bang theory evidence – microwave background radiation
• Kids being Cooked Alive
• Dr Devra Davis: 'The truth about mobile phone and wireless radiation'
• Infrared Ray


  Ever present in almost everything like visible light
• Infrared Ray


  • Heat of objects
  • Heat of the organisms
  • Automatic adjustment of focus in cameras