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Energy-Mass Equivalence Principle. By Albert Einstein. E = mc 2. E = total energy of a system M = total mass of the system C = speed of light. Mass & Energy. Einstein’s equation E = mc 2 shows us that mass and energy are related.
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Energy-Mass Equivalence Principle By Albert Einstein
E = mc2 • E = total energy of a system • M = total mass of the system • C = speed of light
Mass & Energy • Einstein’s equation E = mc2 shows us that mass and energy are related. • When the mass increases, the stored energy inside the mass increases as well.
FYI • Neutrons • Are the cement of the atom. If you add or take away a neutron, then you will have severe instability of the atom.
Example: I put my hedgehog Pepper, who weighs 200g, into a thermonuclear flux capacitor which converts Pepper into pure energy. How much energy do I get out? • E = mc2 • E = 0.200(3.0x108 )2 • E = 1.8x1016 J One hedgehog is enough energy to power the entire country for a little while
Nuclear Fusion • The combining of nuclei of light atoms, such as hydrogen, into heavier nuclei accompanied by the release of much energy.
Nuclear Fusion • Sum of parts of He-3 is 3.0243071738 amu • Actual mass of He-3 is 3.0160293191 amu • The Helium has less mass than its component parts! Where does the extra mass go?
Nuclear Fusion • All elements are made of protons and neutrons that are bound together. • Once they are bound together, they lose mass – really they lose energy. The energy lost is called the “binding energy”.
Nuclear Fission • The splitting of an atomic nucleus into two main parts accompanied by the release of much energy.
Nuclear Fission • Fission is the reverse process of fusion. • Splitting Helium takes energy, so it is not a useful process. • As elements get heavier, it takes more and more energy to keep them together. Some elements are too massive to stay in one piece, so they naturally fall apart. These are radioactive elements.
Uranium is one of these heavy elements. It has 235 nucleons (protons and neutrons) and readily falls apart. • Unlike Helium, Uranium takes energy to keep it together. • When uranium 235 fissions, it splits into Krypton, Barium and 3 neutrons. It also releases mass in the form of a gamma ray. • U Kr + Ba + 3n + γ • This process is called nuclear fission.
So where do we use this stuff? • Radiation • Therapy Diagnostic Imaging Nuclear power Digital Cameras