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Solar Energy

Solar Energy. Properties of the Sun. Distance from the earth 150 000 000 km Mass 333 400 times the mass of Earth Consists of Hydrogen and helium Age 4.6 billion years Lifespan ~10 billion years Rotation time 27 days Surface temperature 5800K

timon-caldwell
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Solar Energy

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  1. Solar Energy

  2. Properties of the Sun • Distance from the earth • 150 000 000 km • Mass • 333 400 times the mass of • Earth • Consists of • Hydrogen and helium • Age • 4.6 billion years • Lifespan • ~10 billion years • Rotation time • 27 days • Surface temperature • 5800K • Corona temperature • ~1 000 000K

  3. The power of the sun comes from fusion The energy of the sun and other stars is from fusion, where hydrogen cores fuse together, producing helium. Every second 600M tons of hydrogen (H) is turned into helium (He). From this 400M tons is turned into energy.

  4. Solar energy arrives to Earth as radiation:E=hf

  5. Black-Body Radiation • All bodies send infrared. • An ideal black body (the Sun, light bulb) absorbs all incoming radiation. This kind of body also emits the same amount of radiation. ( radiative balance) • The hotter the body, the smaller is the wavelenght which is equivalent to the radiations intensity maximum. • With the equivalent wavelength you can determine the temperature of the body: • Wien's displacement law ,

  6. The Black-Body radiation spectrum Max Planck As the temperature decreases the peak of the black- body radiation curve moves to longer wavelenghts.The graphs' shape remains.

  7. Part I An experiment IDeterming the temperature of the ”surface” of the Sun Idea: • Determine the wavelengthcorresponding to the maximumintensity of the spectrum of the Sun • Determine the temperaturebyusingWien'sdisplacementlaw.

  8. Measuredintensityspectrum of the Sun In Orimattila 24.3.2013

  9. Spectrum of the Sun

  10. Results (The temperature of sun,s surface)

  11. Part II PhotoelectricEffect • Electrons' detachment from metal caused by electromagnetic radiation • The smallest frequency, where electromagnetic radiation can detach electrons is called cutoff frequency f0 • If f >f0 =>electrons are detached • Cutoff frequency depends on the metal

  12. Explanation (Einstein 1905 => Nobel 1921) • Light consists of photons, the energy of which is • Photon gives energy to the electrons in the metal, if f > f0 • hf = photons energy • W0= detachment work • Ek =the maximal kinetic energy of detached electrons • h = Planck constant 6,62*10-34Js E metalli 4,135*10-15eVs

  13. An experiment II:Determining Planck’s constant h • To determine Planck´s constant h, we measured the diffusion voltages of multicoloured LEDs as a function of frequency. • The circuit board is equipped with six LEDs in the colours blue, green, yellow and the three different wavelengths of red.

  14. Measurements • Each diode is connected to the voltage source and then we gradually increased the voltage. • The diodes light up when the bias voltage U0 has been reached • The current must be under 20mA, otherwise diodes will burn off.

  15. Measurementresults

  16. Photoelectric Effect

  17. Planck constant is the slope of the straight line. For the sake of simplicity, we left *10^-19 and *10^14 from this grid.

  18. Results Measured:

  19. A light bulb which is powered by a solar cell (Photoelectric effect in practise)

  20. A solar powered toy plane

  21. Dictionary

  22. DICTIONARY • SOLAR ENERGY aurinkoenergia • MASS DEFECT massavaje • BINDING ENERGY sidosenergia • BLACK-BODY RADIATION mustan kappaleen säteily • VIENNA DISPLACEMENT LAW Wienin siirtymälaki • RADIATION säteily • PLANCK CONSTANT Planckin vakio • PHOTOELECTRIC EFFECT valosähköilmiö • AIR-SOURCE HEAT PUMP ilmalämpöpumppu • CORE ydin • CONSISTANCE pysyvyys • GRAPH kaavio, kuvaaja • DISASSEMBLE hajota • INFRARED lämpösäteily • ABSORB imeä • EMIT lähettää • WAVELENGHT aallonpituus • SPECTRUM spektri • PEAK huippu • INTENSITY MAXIMUM intensiteettimaksimi • CONDUCTION johtuminen • STRUCTURAL PARTICLE rakennehiukkanen • CONVECTION kuljettuminen

  23. MEDIUM väliaine • DETACHMENT irtoaminen • CUTOFF FREQUENCY rajataajuus • PHOTON fotoni • KINETIC ENERGY liike-energia • ELECTRIC FIELD sähkökenttä • COUNTER VOLTAGE vastajännite • SOLAR CELL valokenno • APPLICATION sovellus

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