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PPoint Radiasi EM 108RadSafety.pptx - Radiasi...

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Radiasi Elektromagnetik
Electromagnetic Waves…Do not need matter to transfer energy.Are made by vibrating electric charges and can travelthrough space by transferring energy between vibratingelectric and magnetic fields.
Making Electromagnetic WavesWhen an electric charge vibrates, the electric field around itchanges creating a changing magnetic field.The magnetic and electric fields create each other again andagain.An EM wave travels in all directions.The figure only shows awave traveling in one direction.The electric and magnetic fields vibrate at right angles to thedirection the wave travels so it is a transverse wave.
Properties of EM WavesAll matter contains charged particles that are alwaysmoving; therefore,all objects emit EM waves.The wavelengths become shorter as thetemperatureofthe material increases.EM waves carryradiant energy.MaterialSpeed (km/s)Vacuum300,000Air<300,000Water226,000Glass200,000Diamond124,000oAll EM waves travel 300,000km/s in space. (speed of light-nature’s limit!)oEM waves usually travelslowest in solids and fastest ingases.
Spektrum GelombangElektromagnetikThe whole range of EM wave frequencies is called theelectromagnetic spectrum.Different parts of EM waveinteractwith matter in different ways.The ones humans can see are calledvisible light, a small part of thewhole spectrum.
Life & RadiationAll life is dependent on small doses of electromagneticradiation.For example, photosynthesis and vision use the sunsradiation.
Changes to our ElectromagneticEnvironment over Time
Radioactive WasteRadonX-RaysConsumerProductsNuclear PowerNuclearMedicineSolar RadiationCosmic RaysTerrestrial RadiationFood &DrinkEachOtherRADIOACTIVE SOURCES
Terrestrial RadiationCommon radionuclides created during formation of earth:Radioactive Potassium (K-40) found in bananas, throughout the humanbody, in plant fertilizer and anywhere else stable potassium exists.Radioactive Rubidium (Rb-87) is found in brazil nuts among otherthings.Terrestrial radiation comes from radioactivity emitting fromPrimordial radio nuclides- these are radio nuclides left over fromwhen the earth was created.Greatest contributor is226Ra (Radium) with significant levels alsofrom238U,232Th, and40K.Igneous rock contains the highest concentration followed bysedimentary, sandstone and limestone.Fly ash from coal burning plants contains more radiation thanthat of nuclear or oil-fired plants.
Consumer Products and Radioactive MaterialThere are more sources of radiation in the consumerproduct category than in any other.Television sets - low energy x-rays.Smoke detectorsSome more products or services: treatment of agriculturalproducts; long lasting light bulbs; building materials;static eliminators in manufacturing; and luminous dials ofwatches, clocks and compasses
The earth emits radiationcomposed of lower energyinfrared radiationcollectively known aslong-wave radiation(LW)The sun emits radiationcomposed of high energyinfrared radiation,visiblelight, andultravioletradiation collectively knownasshortwave radiation(SW)
Types of Electromagnetic RadiationIonizing Radiation:Non-Ionizing Radiation:
Wavelength, mFrequency, s-1Energy ofonephoton, eVE ~ν~1λ_Types of Electromagnetic Radiation

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Term
Fall
Professor
N/A
Tags
Radioactive Decay, Electromagnetic spectrum, Ionizing radiation, Gamma ray, radioactive material

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