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NIELS BOHR
BOHR’S LIFE AND HIS WORKS
• WHEN AND WHERE WAS OUR SCIENTIST BORN?
• WHAT EXPERIMENTS DID OUR SCIENTIST DO?
• HOW DID SUCH EXPERIMENTS HELP IMPROVEMENT OF ATOMC MODEL?
• HOW DID OUR SCINETIST’S FINDINGS HELP ADVANCEMENT OF OUR
UNDERSTANDING OF ATOMIC STRUCTURE?
WHEN AND WHERE WAS OUR SCIENTIST
BORN?
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In Copenhagen on october 7,1885.
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As the son of Christian Bohr, professor of physiology at Copenhagen University.
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His mother came from a family distinguished in the field of education.
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In 1903, he entered Copenhagen University
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His Master's degree in Physics in 1909 and his Doctor's degree in 1911.
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The award of the Nobel Prize for 1922.
WHAT EXPERIMENTS DID OUR SCIENTIST DO?
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Determination of the surface-tension of water by the method of jet vibration
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The spectra of helium and hydrogen
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Atomic models and X-ray spectra.
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X-ray spectrums and the periodic system of elements
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The polarisation of fluorescent light
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The quantum theory of radiation
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Planck ' s constant and the atomic nucleus
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Atomic structure
HOW DID SUCH EXPERIMENTS HELP IMPROVEMENT OF
ATOMC MODEL?

Surface tension with Sir J.J. Thomson at Cambridge.
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Manchester in March 1912 and joined Ernest Rutherford's group studying
the structure of the atom.
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Bohr was among the first to see the importance of the atomic number.
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Rutherford's nuclear atom was both mechanically and electromagnetically
unstable, but Bohr imposed stability on it by introducing the new and not yet
clarified ideas of the quantum theory being developed by Max Planck, Albert
Einstein, and other physicists. Departing radically from classical physics
THE BOHR MODEL CONSISTS OF FOUR
PRINCIPLES
1) Electrons assume only certain orbits around the nucleus. These orbits
are stable and called "stationary" orbits.
2) Each orbit has an energy associated with it. For example the orbit
closest to the nucleus has an energy E1, the next closest E2 and so on.
3) Light is emitted when an electron jumps from a higher orbit to a lower
orbit and absorbed when it jumps from a lower to higher orbit.
4) The energy and frequency of light emitted or absorbed is given by the
difference between the two orbit energies, e.g.,
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E(light) = Ef - Ei
n = E(light)/h
h= Planck's constant = 6.627x10-34 Js
where "f" and "i" represent final and initial orbits

Bohr postulated that Electrons move around the nucleus in “circular orbits” with
an angular momentum, mvr,given by
mvr=nh/2∏

m = mass of ev = velocity of er = radius of orbit
h = Planck’s constant
n = principle quantum number.
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This description of atomic structure is known as the Bohr atomic model.
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REFERENCES
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http://tr.wikipedia.org/wiki/Bohr_modeli

http://nobelprize.org/nobel_prizes/physics/laureates/1922/bohrbio.html

http://abyss.uoregon.edu/~js/glossary/bohr_atom.html

http://www.colorado.edu/physics/2000/quantumzone/bohr.html

http://www.youtube.com/watch?v=t005KSfs03g&feature=related
THANK YOU FOR
YOUR ATTENTION