Transcript Aurinkoenergia - WordPress.com

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
• 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.
2
3
4
1
H

H

He

1
1
2
0n
Solar energy arrives to Earth as radiation: E=hf
E  hf 
hc

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:
b
λ
=
Wien's displacement law
,
max
T
The Black-Body radiation spectrum
Max Planck
E  hf
As the temperature decreases the peak of the blackbody radiation curve moves to longer
wavelenghts.The graphs' shape remains.
Part I An experiment I
Determing 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.
Measured intensity spectrum of the Sun
In Orimattila 24.3.2013
Spectrum of the Sun
Results
(The temperature of sun,s surface)
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
E  hf
• 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
4,135*10-15eVs
E
Ekmax
hf
W0
metalli
hf  W0  Ekmax
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.
Measurements
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
Photoelectric Effect
hf  W0  Ekmax ,
Ekmax  eU
hf  W0  eU
eU  hf  W0
y  kx  c
eU 0
h
f
Planck constant is the slope of the straight line.
For the sake of simplicity, we left *10^-19 and *10^14 from this grid.
Results
Measured:
A light bulb which is powered by a solar cell
(Photoelectric effect in practise)
A solar powered toy plane
Dictionary
SOLAR ENERGY
aurinkoenergia
GRAPH
kaavio, kuvaaja
MASS DEFECT
massavaje
DISASSEMBLE
hajota
BINDING ENERGY sidosenergia
INFRARED
lämpösäteily
BLACK-BODY
RADIATION
ABSORB
imeä
WIEN´SDISPLACE Wienin
MENT LAW
siirtymälaki
EMIT
lähettää
RADIATION
säteily
WAVELENGH
aallonpituus
PLANCK
CONSTANT
Planckin vakio
SPECTRUM
spektri
PHOTOELECTRIC
EFFECT
valosähköilmiö
PEAK
huippu
mustan
kappaleen
säteily
AIR-SOURCE
HEAT PUMP
Ilmalämpöpumppu
INTENSITY
MAXIMUM
intensiteettimak
simi
CORE
ydin
CONDUCTION
johtuminen
CONSISTANCE
pysyvyys
STRUCTURAL
PARTICLE
Rakennehiukkan
en
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
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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
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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
• MEDIUM väliaine
• DETACHMENT
irtoaminen
• CUTOFF FREQUENCY
rajataajuus
• PHOTON fotoni
• KINETIC ENERGY liikeenergia
• ELECTRIC FIELD
sähkökenttä
• COUNTER VOLTAGE
vastajännite
• SOLAR CELL valokenno
• APPLICATION sovellus