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## Quantum Theory

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**Quantum Theory**Wave- Particle Duality- Wave Model - Particle Model -**“If waves can behave as particles…can particles behave**as waves?” De Broglie Wavelength - Electron Diffraction What is the wavelength of a .145kg baseball traveling at 40m/s?**Photon Absorption and Emission**Energy is Quantized**Energy Level Diagrams & Electronvolts**Electronvolt - Joules > eV eV > Joules A photon of 12.09eV is incident upon a hydrogen atom in a gas cloud with its electron in the ground state… a) What happens? b) What are the possible transitions back to the ground state? What is emitted? c) What is the energy associated with each possible emitted photon in eV and Joules?**Quantum Transitions**Energy of a Photon Energy (J) Energy (J) Frequency(Hz) Wavelength (m) What is the energy in Joules does light with frequency of 5x1014Hz possess? What energy is associated with light having a wavelength of 2.07x10-7 in Joules and eV? Hydrogen Atom λ(m)f(Hz)Energy (J) Energy(eV) 434nm = 486nm = 656nm =**Ionization of Atoms and the Photoelectric Effect**Work Function (Φ) – Threshold Frequency - A 12eV photon is incident upon an electron in the ‘a’ level of Mercury. a) What happens? b) How much energy is used to ionize the atom and where does the leftover energy go? c) How much energy is this in Joules? d) What is the velocity of the knocked out electron? e) What would happen if a photon of 8eV came by? 3 Possibilities for Incoming Photon…**Photon Particle Collisions**An incident photon with a frequency of 7x1014Hz strikes an electron at rest. The electron recoils at 6.62X105m/s after the collision.. Determine the following quantities about the photon Before CollisionAfter Collision Energy f(Hz) λ(m)**Mass Energy Equivalence**Energy (J) Mass (kg) A 1gram of matter is converted to pure energy… a) How much energy would be released? b) How long would a 100W light bulb work with that energy?**Universal Mass Units**1u = What is the equivalent energy of an alpha particle in MeV? Being More Precise… Sum of Parts Proton = 1.0073u Neutron = 1.0087u Helium Nucleus = 4.0016u How much mass seems to have disappeared? What happened to it?**Nuclear Reactions**Fusion - Fission -**Matter & Anti-Matter :**How much energy is required to convert into an electron and positron? What is the frequency of each photon emitted when an electron and positron annihilate? Why is it that 2 electrons cannot annihilate each other?**Standard Model**Examples: What other quark combinations could result in same charge? Antimatter Particles