Name: The Electromagnetic Spectrum - Electrons EM… · Higher Frequency Lower Frequency Name: The...

HigherFrequency

LowerFrequency

Name:TheElectromagneticSpectrumPOGILActivity

Wavelength(λ)-Units:m,cm,nmFrequency(ν)-the#ofwavesthatpassagivenpointinonesecond.Units:Hz,sec-1,waves/sec,1/secTherelationshipbetweenfrequency(f)andwavelength(λ)ofawaveisdescribedbytheequation Wavesspeed=frequencyXwavelengthORc=νλ Allelectromagneticradiationpropagatesataspeedofc=3.00x108m/sec (approximately186,000milespersecond)thisiscalledthespeedoflight!Whensolvingproblemsusingc(thespeedoflight)ν MUSTbeinHzorsec-1andλ�MUSTbeinmeters.Problems

1.Whatisthewavelengthofradiationwithafrequencyof6.24xl013sec-1?

2.Whatisthefrequencyofradiationwithawavelengthof2.20xl0-6nm?(1nm=10-9mor109nm=1m)3.Atelevisionrelaytransmitteroperatesatafrequencyof927.9MHz.Calculatethewavelengthofthesignalinnanometers.Isthisvisiblelight?(1MHz=1,000,000Hz) HowonearthwouldIknowifitisvisiblelight?Readontofindout!!TheNatureofElectromagneticRadiation

Electromagnetic radiation includes radio signals, microwaves, infrared, visible light, ultraviolet, X-rays, andgammarays.Onemodelofelectromagneticradiationisapropagatingwavethatispartiallyelectricinnatureandpartiallymagneticinnature.Thefollowingdiagramisapictorialdescriptionofthismodel:Thistypeofwaveiscalledanelectromagneticwave.TheElectromagneticSpectrumThe electromagnetic spectrum is an ordered list of all the types of electromagnetic radiation. Allelectromagneticradiationcanbedescribedusingthewavemodelorparticlemodelabove.Theonlydifferencebetween each type is thewavelength and frequency of the associated electromagneticwave. The types ofradiationandtheirwavelengthrangesareshowninthediagrambelow.Problems(Usethediagramsonthepreviouspagetoanswerthesequestions.)4.WhatisthedifferencebetweenanX-ray,light,andaradiowave?5.Whichtypeofelectromagneticradiationhas:

Electromagnetic Spectrum

Wavelength Type of Electromagnetic Radiation 5.55 m to 187 m OR (5.55X109 nm to 1.87X1011 nm) AM Radio 0.187 m to 5.55 m OR (1.87X108 nm to 5.55X109 nm) TV & FM Radio Waves

10 mm to 187 mm OR (1X107 nm to 1.87X108 nm) Microwave 750 nm to 1,000,000 nm Infrared (IR)

400 nm to 700 nm Visible spectrum 10 nm to 400 nm Ultraviolet (UV) Less than 10 nm X rays

Less than 0.001 nm Gamma (γ) rays

electric part of wave

magnetic part of wave

direction of propagation

(a) thelongestwavelength?

(b) theshortestwavelength?

(c) thehighestfrequency?

(d) thelowestfrequency?

6.Whatistheapproximaterangeofwavelengthsofvisiblelight?Nowgobackandanswerquestions#3!7.Whatismeantbythestatement“Lightistheonlythingwecansee.”?ElectromagneticRadiationandEnergyElectromagnetic radiation carries energy with it over space. The energy of a photon (a particle ofelectromagneticradiationcarryingaquantumofenergy)isgivenbytheequation Energy=hXfrequencyORE=hν TheconstanthiscalledPlanck'sconstant,equalto6.63x10─34J●sec,averysmallnumber.Frequency(ν)–mustbeinHzorsec-1Anotherequationfortheenergyofaphotonis

Energy=hXspeedoflightORE=hcWavelength λ

Problems 8.Ifacertainlighthas7.18xl0-19Jofenergywhatisthefrequency,inHz,ofthislight?

b. Whatisthewavelength,innm,ofthislight?9.Ifthefrequencyofacertainlightis3.8xl014Hz,whatistheenergyofthislight?10.Theenergyofacertainlightis3.9xl0-19J.Whatisthewavelength,innm,ofthislight?Isitvisible?11. List the types of electromagnetic radiation in order from lowest energy photons to highest energyphotons.