Electromagnetic waves spectrum Electromagnetic waves, spectrum
Electromagnetic waves spectrum Electromagnetic waves, spectrum
Electromagnetic waves spectrum Electromagnetic waves, spectrum
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<strong>Electromagnetic</strong> <strong>waves</strong> <strong>waves</strong>, <strong>spectrum</strong><br />
Oct. 2012<br />
Biophysics 1 st semester<br />
József Orbán<br />
University of Pécs, Department of Biophysics
Light g – electromagnetic g radiation<br />
photon (quantum of radiation energy) : E = h f<br />
Dual nature of light:<br />
<strong>Electromagnetic</strong> wave Particle (photon)<br />
(propagation)<br />
Maxwell<br />
• Diffraction<br />
• Interference<br />
• Polarisation<br />
(reaction)<br />
Einstein<br />
A b s o r p t i o n<br />
R e f l e c t i o n<br />
• Photoelectric effect<br />
• Compton effect
Propagation of electromagnetic wave<br />
If = 600 nm then<br />
If = 600 nm, then<br />
f = 5·10 14 Hz<br />
x<br />
direction of<br />
propagation
E<br />
Propagation of electromagnetic wave<br />
electric field<br />
strength<br />
vector t<br />
x<br />
magnetic field<br />
strength vector<br />
B<br />
x<br />
transversal<br />
wave<br />
T: period time (in time)<br />
λ: wavelength (in space)<br />
c = f<br />
The electric- and the magnetic field strength vectors are<br />
perpendicular to each other and to the direction of<br />
propagation, ti as well!<br />
ll!<br />
x
Linearly y (plane) (p ) polarised p light g<br />
If the electric field’s field s strength vector<br />
oscillates in only one plane all along the<br />
propagation then the wave is called<br />
li linearly l or plane l polarised. l i d<br />
If it is true in each point of space in a light<br />
beam, then the beam is polarised, as well.<br />
http://esr.elte.hu/~noemi/labor/cd/demo0.html<br />
Animations show a<br />
vertically polarised<br />
electromagnetic wave (it’s<br />
electric field’s field s oscillation) oscillation).<br />
View from the perpendicular plane:
These animations show a horizontally polarised wave wave.<br />
Linearly (plane) polarised.<br />
Vi View ffrom the h perpendicular di l plane l <br />
http://esr.elte.hu/~noemi/labor/cd/demo0.html
Total spectra p of electromagnetic g radiations<br />
Energy, frequency (E=hf Wavelength (=1/f)<br />
Gamma<br />
X-ray (Röntgen)<br />
Visible range: light<br />
E = hf<br />
c = f
name of<br />
the range
Electronic energy gy levels of atoms<br />
Bohr- and quantummechanic atommodel<br />
Electrons have quantised (defined) energy→ energy levels!<br />
energy (level) energy difference<br />
Figures are only for demonstration!
Spectrum p<br />
Spectrum:<br />
• (light) ( g ) intensityy or analogous g quantity q y -<br />
plotted against<br />
• wavelength or frequency frequency.<br />
CLASSIFICATION OF SPECTRA<br />
Source:<br />
Types:<br />
• absorption ( atoms )<br />
• line ( atoms )<br />
• emission ( production p ) • band ( molecules )<br />
• continuous ( any material at<br />
high temperature: black body<br />
radiation )
Continuous Continuous, emission<br />
Line, emission<br />
Continuous, emission<br />
Line, emission<br />
Types of <strong>spectrum</strong><br />
I<br />
See: continuous emission radiation radiation, black body body, Planck Planck, Stefan Stefan-Boltzman<br />
Boltzman<br />
Source of images: http://csep10.phys.utk.edu/astr162/lect/light/absorption.html
absorption<br />
Continuous, emission<br />
Line, emission<br />
Line Line, absorption<br />
Types of <strong>spectrum</strong><br />
I<br />
See: continuous emission radiation radiation, black body body, Planck Planck, Stefan Stefan-Boltzman<br />
Boltzman<br />
Source of images: http://csep10.phys.utk.edu/astr162/lect/light/absorption.html
S p e c t r a<br />
Line type emission spectra of different atoms:
Band type yp (absorption) ( p ) <strong>spectrum</strong> p<br />
Absorpption<br />
2,5<br />
2,0<br />
1,5<br />
1,0<br />
0,5<br />
00 0,0<br />
of ACTIN molecule<br />
How can you explain the shape?<br />
The line spectra of atoms and<br />
band spectra of molecules are<br />
characteristic!<br />
(depends on their chemical<br />
constitution) tit ti )<br />
actin<br />
260 270 280 290 300 310 320<br />
Wavelength (nm)
Absorption p of proteins p - aminoacids<br />
There are 3 aminoacids that<br />
absorbs in UV UV.<br />
(Measuring the absorption spectra<br />
of protein solution solution, the<br />
concentration can be determined.)<br />
Exttinctionn<br />
coeefficientt<br />
wavelength g
our SUN
Mitosis of Rat kangoroo kidney epithelial cell<br />
DNS Mi Microtubuli t b li Mit Mitochondria h d i<br />
forrás: http://micro.magnet.fsu.edu/cells/fluorescencemitosis/index.html3