S OLAR E NERGY. P ROPERTIES OF THE S UN Distance from the earth 150 000 000 km Mass 333 400 times...
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Transcript of S OLAR E NERGY. P ROPERTIES OF THE S UN Distance from the earth 150 000 000 km Mass 333 400 times...
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
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.
nHeHH 10
42
31
21
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 ,λmax=bT
The Black-Body radiation spectrum
As the temperature decreases the peak of the black- body radiation curve moves to longer wavelenghts.The graphs' shape remains.
Max Planck
hfE
Part I An experiment IDeterming the temperature of the
”surface” of the Sun
Idea: •Determine the wavelength corresponding to the maximum intensity of the spectrum of the Sun•Determine the temperature by using Wien's displacement law.
Part II Photoelectric Effect• 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
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
hf
0W
maxkE
max0 kEWhf
hfE
metalli
4,135*10-15eVs
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.
Measurement results colour f / in 1014 Hz U0 / V E=eU /J*10-19
465 Blue 6.22 (2.86) Failed result
560 Green 5.16 1.72 2.76
585 Yellow 4.94 1.65 2.64
635 Red #1 4.55 1.51 2.42
660 Red #2 4.38 1.48 2.37
Planck constant is the slope of the straight line.
For the sake of simplicity, we left *10^-19 and *10^14 from this grid.
DictionarySOLAR ENERGY aurinkoenergia GRAPH kaavio, kuvaaja
MASS DEFECT massavaje DISASSEMBLE hajota
BINDING ENERGY
sidosenergia INFRARED lämpösäteily
BLACK-BODY RADIATION
mustan kappaleen säteily
ABSORB imeä
WIEN´SDISPLACEMENT LAW
Wienin siirtymälaki
EMIT lähettää
RADIATION säteily WAVELENGH aallonpituus
PLANCK CONSTANT
Planckin vakio SPECTRUM spektri
PHOTOELECTRIC EFFECT
valosähköilmiö PEAK huippu
AIR-SOURCE HEAT PUMP
Ilmalämpö-pumppu
INTENSITY MAXIMUM
intensiteettimaksimi
CORE ydin CONDUCTION johtuminen
CONSISTANCE pysyvyys STRUCTURAL PARTICLE
Rakennehiukkanen
MEDIUM väliaine CONVECTION Kuljettumine
DETACHMENT irtoaminen PHOTON fotoni
CUTOFF FREQUENCY
rajataajuus KINETIC ENERGY liike-energia
ELECTRIC FIELD sähkökenttä COUNTER VOLTAGE
Vastajännite
SOLAR CELL valokenno APPLICATION sovellus
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