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Electromagnectic Spectrum. Chapter 1 section 2. Electromagnetic Spectrum. Visible light is part of a larger spectrum. (James Maxwell, 1852) Visible light is only a small part of the Electromagnetic Spectrum.
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Electromagnectic Spectrum Chapter 1 section 2
Electromagnetic Spectrum • Visible light is part of a larger spectrum. • (James Maxwell, 1852) • Visible light is only a small part of the Electromagnetic Spectrum. • Each color of visible light is a different wavelength of electromagnetic radiation.
Nature of Electromagnetic Waves • Humans can see radiation from Red (longest) through to Violet (shortest). • They travel as vibrations in electrical and magnetic fields. • Speed of electromagnetic waves = 300,000,000 meters/second (Takes light 8 minutes to move from the sun to earth {150 million miles} at this speed.)
Waves of the Electromagnetic Spectrum Ultraviolet Rays Gamma Rays Radio Waves Infrared Rays Visible Light X-Rays Microwaves
RADIO WAVES • Have the longest wavelengths and lowest frequencies of all the electromagnetic waves. • Radios pick up radio waves through an antenna & converts it to sound waves. • Radio stations broadcasts at different frequencies. • MRI (MAGNETIC RESONACE IMAGING) • Uses Short wave radio waves with a magnet to create an image
MICROWAVES • Microwaves—have shorter wavelengths andhigher frequency than radio waves. • microwave ovens. • Heat waves that transfers Energy to the food, so it cooks • 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.
INFRARED RAYS • Infrared are found below red • Shorter wavelength and higher frequency than microwaves. • You can feel the longest ones as warmth on your skin • Heat lamps give off infrared waves. • Warm objects give off more heat energy than cool objects. • Thermogram—picture that shows regions of different temp. in the body. Temp. is calculated by the amount of infrared radiation given off.
VISIBLE LIGHT • Shorter wavelength and higher frequency than infrared rays. • Electromagnetic waves we can see. • Longest wavelength= red light • Shortest wavelength= violet (purple) light • When light enters a new medium it bends (refracts). Each wavelength bends a different amount allowing white light to separate into it’s various colors ROYGBIV.
VISIBLE LIGHT • VIOLET PHOTONS have the highest energies and the highest frequencies. • RED PHOTONS have lower energies and lower frequencies.
ULTRAVIOLET RAYS • Shorter wavelength and higher frequency than visible light • Carry more energy than visible light • Used to kill bacteria. (Sterilization of equipment) • Causes your skin to produce vitamin D (teeth and bones) • Can cause skin cancer. .. Use sunblock!!!! • Used to treat jaundice
X- RAYS • Shorter wavelength and higher frequency than UV-rays • Carry a great amount of energy • Can 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)
GAMMA RAYS • Shorter wavelength and higher frequency than X-rays • Carry 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.
SUMMARY • All electromagnetic waves travel at the same speed. (300,000,000 meters/second in a vacuum.) • They all have different wavelengths and different frequencies. • Long wavelength-lowest frequency • Short wavelength highest frequency • The higher the frequency the higher the energy.