PHY10 (for MT1)

PHY10 (for MT1) - NatureofLight(Ch.5inbook) 08:32...

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Nature of Light (Ch. 5 in book) 08:32 -light carries radiative energy -energy measured in joules power-rate of energy flow (measured in watts) white light-all colors of rainbow diffraction grating-plastic with closely spaced lines Light interacts with matter in 4 ways… Emission-light bulb emits visible light Absorption-when you place hand near a light bulb your hand absorbs some of  the light making your hands warm (opaque) Transmission-glass/air transmit light; let light pass thru Reflection/scattering-light can bounce off matter leading to what we call  reflection (bouncing in same direction) or scattering  WAVE LENGTH AND FREQUENCY *wavelength, frequency, hertz -light waves are vibrations of both electric and magnetic fields caused by motions  of charged particles (is an electromagnetic wave  speed of light=c=300000 km/sec, 3x10^5 km/s, 3x10^8m/s
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-light is particle and wave ELECTROMAGNETIC SPECTRUM     electromagnetic spectrum-complete spectrum of light  -visible light has wavelengths of 400nm to 700nm (blue or violet end) infrared-light with wavelengths longer than red light, lies beyond red end of  rainbow radio waves-longest wavelength, a form of light not sound ultraviolet- shorter wavelength than blue light, lies beyond the blue end of  rainbow -xrays gamma rays-shortest wavelength LIGHT AND TEMPERATURE     -photon energies depend only on the object’s temperature regardless of what is  made of  thermal radiation/blackbody radiation-the temperature dependence of this light  (its spectrum is called thermal radiation spectrum)
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Laws of thermal radiation… Stefan-Boltzmann law-each sq meter of a hotter object’s surface emits more  light at all wavelengths  Wien’s law-hotter objects emit photons with a higher average energy which  means shorter avg wavelength THE DOPPLER SHIFT     -Doppler effect causes shift in wavelengths of light -gives us direction not speed blueshift-coming to us, shorter wavelength redshift-moving away from us, longer wavelength *math insight p. 173 ROTATION RATE OF DISTANT OBJECT     *figure 5.25 on p. 174
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Ch.20 Galaxies and Foundation of Cosmology  08:32 cosmology- study of overall structure and evolution of the universe
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This note was uploaded on 09/27/2011 for the course TXC 8 taught by Professor Na during the Spring '11 term at UC Davis.

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PHY10 (for MT1) - NatureofLight(Ch.5inbook) 08:32...

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