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Electromagnetic Spectrum
The electromagnetic spectrum consists of electromagnetic waves that differ in frequency and wavelength. It ranges from gamma rays with the highest frequency and shortest wavelength to radio waves with the lowest frequency and longest wavelength. All electromagnetic waves travel at the speed of light and are classified based on their position within the electromagnetic spectrum according to their frequency or wavelength.
Electromagnetic Spectrum
- 1. Electromagnetic Spectrum Physics 1, Group 6, Rosal 2015
- 2. James Clerk Maxwell With the equations he formulated on electromagnetic induction, he found that these equations had a speed of ~3.00 x 108 m/s w/c is equal to the speed of light Discovered the nature of light (as electromagnetic waves) Light wave as a transverse wave
- 3. Electromagnetic Radiation Made of electric and magnetic fields vibrating, acc to wave theory, at right angles to one another and moving through space at the speed of light Form of ENERGY that can travel through empty space Classified across the spectrum by its wavelength A transverse wave consisting of oscillating electric and magnetic
- 5. Electromagnetic Spectrum All EM waves travel at the same speed in a vacuum, they differ from one another in their frequency & wavelength Classification of EM waves according to frequency Light is simple EM waves in this range of frequencies Ex. Accelerating electric charge -> radiate in electric and magnetic fields
- 7. Radio waves Examples:radio stations, stars, aircraft and shipping bands, TV and fm radio, astronomical bodies, lightning, can transmit info Low wavelength, low frequency, low energy
- 8. Microwaves Microwaves inspace are used by astronomers to learn about the structure of nearby galaxies, and our own Milky Way! Can penetrate through smoke, haze, clouds, and even light rain Ex. Microwaves radar, transmit data, satellite imagery
- 9. Infrared Our skinemits infrared light, which is why we can be seen in the dark by someone using night vision goggles. In space, IR light maps the dust between stars. Even that we can not see or hear infrared, we can feel it at our skin temperature sensors.
- 10. Color Frequency Wavelength violet 668–789 THz 380–450 nm blue 606–668 THz 450–495 nm green 526–606 THz 495–570 nm yellow 508–526 THz 570–590 nm orange 484–508 THz 590–620 nm red 400–484 THz 620–750 nm Visible spectrum
- 11. Visible Spectrum Portionof the electromagnetic spectrum that is visible to (can be detected by) the human eye. corresponds to a band in the vicinity of 400–790 THz. Reflects light off objects from any light source Visible sunlight passes through the earth’s atmosphere and reflects off objects allowing us to see them
- 13. Why does aCD reflect rainbow colors? Like water drops in falling rain, the CD separates white light into all the colors that make it up. The colors you see reflecting from a CD are interference colors, like the shifting colors you see on a soap bubble or an oil slick. You can think of light as as being made up of waves-like the waves in the ocean. When light waves reflect off the ridges on your CD, they overlap and interfere with each other. Sometimes the waves add together, making certain colors brighter, and sometimes they cancel each other, taking certain colors away.
- 14. Why does aCD reflect rainbow colors? On a CD, the surface is mirrored so the rainbow colors are much more intense. the angle controls the path difference.
- 15. Ultraviolet Ex. Sun,stars and other “hot objects in space emit UV radiation, “ultraviolet” because its frequency is just a bit higher than visible violet light, in gadgets, black light lamps 10 nm- 400 nm
- 16. X-Ray Naturally emittedby space objects like neutron stars, black holes, binary stars, remnants of super nova, stars, comets, and even our own sun X-ray images are produced when they are absorbed by what they strike and, leaving shadows on the film that imprints in an image 3nm – 0.3 nm
- 17. Gamma Rays Smallestwavelength Ex. Nuclear power plants, big particle accelerators, stars, radiotherapy- used to kill cancer cells (gamma knife), kills microorganisms in food through irradiation, sterilizing medical equipment Biggest gamma ray generator: naturally produced in the hottest regions of the universe
- 19. Light Comparison (fand λ) LIGHT COMPARISON Name Wavelength Frequency (Hz) Gamma Ray Less than 0.02 nm More than 15 EHz X-Ray 0.01 nm – 10 nm 30 EHz – 30 PHz Ultraviolet 10 nm – 400 nm 30 PHz – 760 THz Visible 390 nm – 750 nm 770 THz – 400 THz Infrared 750 nm – 1mm 400 THz – 300 GHz Microwave 1 mm – 1 m 300 GHz – 300 MHz Radiowaves 1 mm – 100, 000 300 GHz – 3 Hz km