Electro magnetic wave(bpp)

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  • ELECTROMAGNETIC WAVES By Mr. Chaiporn Pattanajak

  • When an electric field changes, so does the magnetic field. The changing magnetic field causes the electric field to change. When one field vibratesso does the other.

    The classification of electromagnetic waves according to frequency.

  • Nature of Electromagnetic WavesThey are Transverse waves without a medium. (They can travel through empty space)Energy carrying waves emitted by vibrating charges often electrons that is composed of oscillating electric and magnetic fields that generate one another.

  • Electromagnetic WavesGamma raysX-rayUltravioletVisible light (ROYGBV)

  • Electromagnetic WavesInfraredMicrowaveRadio wave

  • Electromagnetic WavesAll EM waves move at the same speed in a vacuum and differ from one another in frequency and wavelenght.

  • Electromagnetic Waveslonger wavelength=low frequency=low energyShort wavelenght=high frequency=high energy

  • Electromagnetic WavesGamma raysX-rayUltravioletVisible light (ROYGBV)InfraredMicrowaveRadio wave

  • Electromagnetic WavesThe speed of all the waves in the EM spectrum is equivalent to the speed of light 299 792 453 m/s. (300,000,000m/s)

  • Electromagnetic WavesYou know more about the electromagnetic spectrum than you may think.

  • Electromagnetic Spectrumname for the range of electromagnetic waves when placed in order of increasing frequencyClick here (AnimationSize of EMwaves)








    Waves of the Electromagnetic

  • Radio Waves

    Have the longest wavelengths and lowest frequencies of all the electromagnetic waves.B. A radio picks up radio waves through an antenna and converts it to sound waves.

  • Radio waveYour radio captures radio waves emitted by radio stations, bringing your favorite tunes. Radio waves are also emitted bystarsand gases in space.

  • Radio Waves

    Radio waves

  • Microwaveshave the shortest wavelengths and the highest frequency of the radio waves.Used in microwave ovens.Waves transfer energy to the water in the food causing them to vibrate which in turn transfers energy in the form of heat to the food.Used by cell phones and pagers.RADAR (Radio Detection and Ranging)Used to find the speed of an object by sending out radio waves and measuring the time it takes them to return.


  • MicrowaveMicrowave radiation will cook your popcorn in just a few minutes, but is also used byastronomersto learn about the structure of nearbygalaxies.

  • Microwaves


  • Infrared= below redShorter wavelength and higher frequency than microwaves.You can feel the longest ones as warmth on your skinHeat lamps give off infrared waves.Warm objects give off more heat energy than cool objects.Thermograma picture that shows regions of different temperatures in the body. Temperatures are calculated by the amount of infrared radiation given off. Therefore people give off infrared rays.

    Infrared rays

  • InfraredNight vision goggles pick up the infrared light emitted by our skin and objects with heat. In space, infrared light helps us map thedustbetween stars.

  • Infrared radiation

    Infrared radiation

  • Shorter wavelength and higher frequency than infrared rays.Electromagnetic waves we can see.Longest wavelength= red lightShortest wavelength= violet (purple) light

    Visible light

  • Visible LightOur eyes detect visiblelight. Fireflies, light bulbs, and stars all emit visible light.

  • Visible light

    Visible light

  • Shorter wavelength and higher frequency than visible lightCarry more energy than visible lightUsed to kill bacteria. (Sterilization of equipment)Causes your skin to produce vitamin D (good for teeth and bones)Used to treat jaundice ( in some new born babies.Too much can cause skin cancer. Use sun block to protect against (UV rays)

    Ultra-violet rays

  • UltravioletUltraviolet radiation is emitted by the Sun and are the reason skin tans and burns. "Hot" objects in space emit UV radiation as well.

  • Ultra-violet radiation

    Ultra-violet radiation

  • Shorter wavelength and higher frequency than UV-raysCarry a great amount of energyCan penetrate most matter.Bones and teeth absorb x-rays. (The light part of an x-ray image indicates a place where the x-ray was absorbed)Too much exposure can cause cancer (lead vest at dentist protects organs from unnecessary exposure)Used by engineers to check for tiny cracks in structures.The rays pass through the cracks and the cracks appear dark on film.


  • X-rayA dentist uses X-rays to image your teeth, and airport security uses them to see through your bag. Hot gases in the Universealso emit X-rays.

  • X-rays


  • Shorter wavelength and higher frequency than X-raysCarry the greatest amount of energy and penetrate the most.Used in radiation treatment to kill cancer cells.Can be very harmful if not used correctly.

    Gamma rays

  • Gamma rayDoctors use gamma-ray imaging to see inside your body. The biggest gamma-ray generator of all is the Universe

  • Gamma rays

    Gamma radiation

  • CREATE A CONCEPT MAPCreate a concept map about EM waves and speed of light.

  • 3-2-1 EXIT CARD3-What have you learned today? Explain.2-What life lessons have you gained from the topic?1-What MI Activity did you learn the most from?