As an object gets hot, it gives Off 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 account For blackbody radiation.

The ultraviolet catastrophe is The contradiction between the Predictions of classical physics And the experimental data for The electromagnetic radiation Of a blackbody in the Ultraviolet end of the spectrum. Experimental data for blackbody Radiation support the quantization Of energy.

Quantization was discovered by Max Planck at the beginning Of the 20 th century. A quanta is a packet of energy. Atoms can only give off, or absorb Energy by units of quanta.

After many experiments and Calculations, he discovered E = h f energy frequency Planck’s Constant X J*s

The pendulum of a clock swings Back and forth with a frequency Of 2 Hz. How much energy would Be carried away in one quantum? E = 1.3 X

Classical physics cannot explain The photoelectric effect. The photoelectric effect is the Emission of electrons from a Surface that occurs when light Of certain frequencies Shines on the surface.

In photoelectric effect, electrons Are ejected from the surface of a Metal when light shines On that metal. Discovered by Einstein

The stopping potential of a certain Photocell is 4 V. What is the kinetic Energy given to the electrons by Incident light? Give your answer In Joules and Electron Volts. 6.4 x J 4.0 eV

Einstein used Planck’s idea To say that light also behaved With quanta. These “quanta” are called photons. This is called the wave-particle Duality of light.

The Compton shift supports the Photon theory of light. The Compton shift is the change In wavelength between incoming And 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 = EhEh

What is the de Broglie wavelength Of a 50 g rock with a speed Of 40 m/s? λ = 3.32 X

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 where The 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 founders Of quantum theory, but he did Not want to believe that Probability was the final Description of nature. He said “ In any case, I am Convinced that God does not Play dice.”