1. Blackbody A black body is an ideal system that absorbs all radiation incident on it The electromagnetic radiation emitted by a black body is called blackbody radiation Wien’s displacement law λ max T = 2.898 x 10 -3 m.K Stefan’s law

2. Max Planck In 1900 Planck developed a theory of blackbody radiation that leads to an equation for the intensity of the radiation (see in the class how to take limits). This equation can fit with experimental data h = 6.626 x 10 -34 J.s h is a fundamental constant of nature

3. Photoelectric Effect The emitted electrons are called photoelectrons

5. Compton Effect

6. The graphs show the scattered x-ray for various angles The shifted peak, λ’ is caused by the scattering of free electrons Compton wavelength is Compton shift equation

7. Absorption Spectrum Emission Spectra

8. Hα is red, λ = 656.3 nm Hβ is green, λ = 486.1 nm Hγ is blue, λ = 434.1 nm Hδ is violet, λ = 410.2 nm In 1885, Johann Balmer found an empirical equation that correctly predicted the four visible emission lines of hydrogen R H is the Rydberg constant R H = 1.097 373 2 x 10 7 m -1 n is an integer, n = 3, 4, 5,…

9. Lyman series: Paschen series: Brackett series:

10. J. J. Thomson Raisin cake Rutherford Formal student of Thomson At Cambridge Geiger Marsden Rutherford worked with his students at the U of Machester

11. Arrival of the Quantum Hero, Niels Bohr He knew that the work of Planck and Einstein on light radiation was very important,, not just clever German ideas. Until he discovered the Balmer series by mixing classical and quantum physics, also using two postulations: (see proof in the class) 1. 2.

12. Louis de Broglie He predicted the wave nature of electrons postulated that because photons have both wave and particle characteristics, perhaps all forms of matter have both properties The de Broglie wavelength of a particle “Electron standing waves in an atom only certain Wavelengths will fit around a circle”

13. In his thesis, he started with Einstein’s Formula Wavelength decreases as momentum increases One of his committee (Paul Langevin) had forwarded his thesis to Einstein

14. Electron Diffraction The slit widths are small compared to the electron wavelength

15. Davisson-Germer Experiment If particles have a wave nature, then they should exhibit diffraction effects Bragg’s Law

16. The phase speed of a wave in a wave packet is given by –This is the rate of advance of a crest on a single wave The group speed is given by –This is the speed of the wave packet itself Wave packet

17. Werner Heisenberg Solve problems in the class and tutoring class

18. Erwin Schrodinger The Schrödinger equation as it applies to a particle of mass m confined to moving along the x axis and interacting with its environment through a potential energy function U(x) is This is called the time-independent Schrödinger equation

19. A Particle in an infinite potential well The lowest allowed energy corresponds to the ground state E n = n 2 E 1 are called excited states E = 0 is not an allowed state, The particle can never be at rest

20. A Particle in a finite potential well