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Blackbody radiation is the Electromagnetic radiation
Emitted by a blackbody, which Absorbs all incoming radiation and
Then emits radiation based Only on its temperature.
Classical physics cannot accountFor blackbody radiation.
The ultraviolet catastrophe is The contradiction between the Predictions of classical physicsAnd the experimental data for The electromagnetic radiation
Of a blackbody in the Ultraviolet end of the spectrum.
Experimental data for blackbodyRadiation support the quantization
Of energy.
Quantization was discovered byMax Planck at the beginning
Of the 20th century.
A quanta is a packet of energy.
Atoms can only give off, or absorbEnergy by units of quanta.
After many experiments andCalculations, he discovered
E = h f
energyfrequency
Planck’sConstant
6.626 X 10-34 J*s
The pendulum of a clock swingsBack and forth with a frequencyOf 2 Hz. How much energy wouldBe carried away in one quantum?
E = 1.3 X 10-33
Classical physics cannot explainThe photoelectric effect.
The photoelectric effect is the Emission of electrons from a
Surface that occurs when lightOf certain frequencies Shines on the surface.
In photoelectric effect, electronsAre ejected from the surface of a
Metal when light shines On that metal.
Discovered by Einstein
The stopping potential of a certainPhotocell is 4 V. What is the kineticEnergy given to the electrons by Incident light? Give your answer
In Joules and Electron Volts.
6.4 x 10-19 J 4.0 eV
Einstein used Planck’s ideaTo say that light also behaved
With quanta.
These “quanta” are called photons.
This is called the wave-particleDuality of light.
The Compton shift supports thePhoton theory of light.
The Compton shift is the change In wavelength between incomingAnd scattered electromagnetic
Waves.
The photoelectric effect is the Reason why there is sound
During a movie.
He referred to the wavelike Behavior of particles matter waves.
De Broglie was awarded the Nobel Prize for his work.
The wavelength of matter Waves depends on the momentum.
λ = h
mv
The frequency of matter waves Depends on energy.
f = Eh
In 1927 Werner Heisenberg Proposed his uncertainty
Principle.
His principle states that the Position and the momentum of
A moving object cannot Simultaneously known.
Attempting to locate an Electron will change the way
It is moving.
The density of an electron cloud Is called electron density.
Electron clouds are dense whereThe probability of finding an
Electron is great.
An atomic orbital is a region Around the nucleus of an atom Where an electron is likely to
Be found.
There are several different kinds of Orbitals, each having a different
Fundamental shape.
Einstein was one of the foundersOf quantum theory, but he did
Not want to believe that Probability was the finalDescription of nature.
He said “ In any case, I amConvinced that God does not
Play dice.”
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