As an object gets hot, it givesOff energy in the form of

Electromagnetic radiation.

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.

If energy has a dual nature, How about matter?

Louis de Broglie thought so.

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

What is the de Broglie wavelengthOf a 50 g rock with a speed

Of 40 m/s?

λ = 3.32 X 10-34

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.”