ELECtromagnetic wavesTitleSlide 3Slide 4What’s on Exam #3?A sound waveSound WavesLightMaxwell’s EquationsWhich way is the electric field at P pointing?Slide 11There is also a current here so there is one of those B things.Both TogetherPropagation of LightSlide 15Waving AlongSir IsaacThe Electromagnetic SpectrumPolarizationSlide 20Changing It AroundCrossed Polarizer's can Transmit light!Big Money!Today’s ExperimentGet a Blue Box and get to work!!!Light etc.PHY 2054 Spring 2011April 13, 2011•Today we start the study of electromagnetic waves and LIGHT as in “let there be”.•This will lead to a discussion of–Polarization–Mirrors–Lenses–Perhaps interference and diffraction•There are available experiments for each of these. Not sure how far we will get but we will get there quickly!Sunday Monday Tuesday Wednesday Thursday Friday Saturday1 23 4 Complete Induction5 6AC7 8ACQuiz?910 11COMPLETEAC EXPT12 13 OPTICSEM WavesPOLARIZATION14 15 OPTICSQuiz1617 18EXAM #3(No Optics)19 20 OPTICS 21 22 OPTICS 2324 25 (LAST LASS)OPTICS26 27 28 29 30 FINALHPA 1199:00 AMApril 2011 Time is on the move!April 2011 Time is on the move!WHEREISTHEFINALEXAM??What’s on Exam #3?Questions!5 Multiple choice questionsThree problems coveringMagnetismInductionAC CircuitsA sound waveA. is a transverse waveB. is a longitudinal waveC. travels at the speed of lightD. has a color spectrumSound WavesLightJames Clerk Maxwell (1831 - 1879) was a genius who studied the properties of Electricity and Magnetism. He took a mathematical approach. He published his first scientific paper when he was 15 years old.The four mathematical equations Maxwell produced are ranked with Sir Isaac Newton's laws of motion and Albert Einstein's theory of relativity as the most fundamental contributions to (“classical” )physics. Maxwell’s equations predicted that the electric field and the magnetic field could propagate through empty space.The calculated velocity of these waves turned out to match the speed of light to a very close precision.It was later demonstrated that these waves were, in fact, light waves.Maxwell’s EquationsGauss’s LawNo Mag Poles!!Faraday’s LawAmpere’s LawDisplacementCurrentd�� D���Which way is the electric field at P pointing? PA LeftB RightC UpD DownE In/OutElectromagnetic Wave GenerationThere is also a current here so there is one of those B things.Both TogetherPropagation of LightThe electric and magnetic fields are predicted (and verified) to be perpendicular to each other.The propagation velocity is found to be “c”, the speed of light in a vacuum.c=3x108 m/sec.Maxwell calculated that the speed of light in a vacuum to be0 01ce m=Propagation of LightSince the E and B fields (vectors) are perpendicular to the direction of propagation, the wave is said to be TANSVERSE.Because of this fact, the light wave can be “polarized”The wavelength of the wave is shown in the diagram.The product of the frequency and the wavelength is c so we see that light can come in different wavelengths (c is a constant)0 01ce m=Waving AlongSir IsaacThe Electromagnetic SpectrumPolarizationPolarizedUnpolarizedPolarizationChanging It AroundCrossed Polarizer's can Transmit light!Big Money!Today’s ExperimentPolarized LightRead the material at the beginning of the experiment that we haven’t coveredDon’t read what we covered todayDo the experimentNext time the math!Get a Blue Box and get to work!!!
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