Nuclear energy equivalent

Beta radiation Electron emission from unstable nuclei, 26,30,528 Binary molecular compound, 41-42,190 Binding energy Energy equivalent of the mass defect measure of nuclear stability, 522,523 Bismuth (m) sulfide, 540 Blassie, Michael, 629 Blind staggers, 574 Blister copper, 539 Blood alcohol concentrations, 43t Body-centered cubic cell (BCC) A cubic unit cell with an atom at each comer and one at the center, 246 Bohrmodd Model of the hydrogen atom... 

Nuclear binding energy is the energy equivalent (in E = mc2) of the difference between the mass of the nucleus of an atom and the sum of the masses of its uncombined protons and neutrons. For example, the mass of a He nucleus is 4.0026 amu. The mass of a free proton is 1.00728 amu, and that of a free neutron is 1.00866 amu. The free particles exceed the nucleus in mass by... 

When energy equivalent to the difference between the energy levels is applied to the system, a transition from the lower to the higher energy level occurs. In NMR spectroscopy, the applied energy that allows this nuclear magnetic dipole transition to occur is a radio-frequency magnetic field, Hx, which is applied perpendicularly to H0. 

One of the most important nuclear properties that can be measured is the mass. Nuclear or atomic masses are usually given in atomic mass units (amu or u) or their energy equivalent. The mass unit u is defined so that the mass of one atom of 12C is equal to 12.0000. .. u. Note we said atom. For convenience, the masses of atoms rather than nuclei are used in all calculations. When needed, the nuclear mass mllucl can be calculated from the relationship... 

In many tabulations of nuclear properties, such as that in Appendix B, the quantity that is tabulated is the mass excess or mass defect rather than the mass. The mass excess, A, is defined as M(A, Z) — A, usually given in units of the energy equivalent of mass. Since in most, if not all calculations, the number of nucleons will remain constant, the use of mass excesses in the calculations will introduce an arithmetic simplification. Another term that is sometimes used is the mass excess per nucleon or the packing fraction [=(M — A)/A]. 

Discussion of Photoelectron and Photofragment Images. The simplest picture for photoexcitation of a molecular Rydberg state would be that of a vertical transition (Av = 0), producing only O2, X(2Ilg)(t = 2) (direct ionization) in the example case. Here electronic motion (ionization) is assumed to be much faster than nuclear motion (dissociation). 02 is much more complicated, of course, and some of the deviations from the simplistic picture could be due not only to the molecule but also to the unconventional three-photon preparation scheme. It is thus important to consider the differences in one-photon and stepwise (2 + 1) excitation. Even with direct one-photon excitation at the energy equivalent of three laser photons, it is known, [78] for example, that the quantum yield for ionization is only 0.5 the other half of the molecules do, in fact, dissociate. 

The mass of a nucleus is determined by the number of protons plus the number of neutrons which it contains. This sum is termed the mass number, and gives the approximate mass of the nucleus, since both protons and neutrons have a mass of about 1 A.M.U. The exact mass could be obtained from the sum of the proton and neutron masses if the mass equivalent of the nuclear energy were known. 

Region Oil (1,000 bbl daily) Coal (Mt oil equivalent) Natural gas (billion m3) Nuclear energy (Mt oil equivalent) Primary energy (Mt oil equivalent) Hydroelectricity (Mt oil equivalent)... 

The third fact is that spent nuclear fuel is not waste. Spent nuclear fuel contains 2% to 3% waste, but is about 97% recoverable uranium and plutonium. Each bundle has the potential electric energy equivalent of more than 10 million barrels of oil. High-level nuclear wastes consist of fission products and actinides that are extracted from spent fuel, but not saved for commercial use or research. Spent fuel may be temporarily stored until it is reprocessed to separate the waste from the valuable plutonium and uranium. The remaining glassified waste will then be permanently entombed. 

Just as an ordinary chemical equation is a shortened version of the complete thermochemical equation which expresses both energy and mass balance, each nuclear equation has a term (written or implied) expressing energy balance. The symbol Q is usually used to designate the net energy released when all reactant and product particles of matter are at zero velocity. Q is the energy equivalent of the mass decrease (discussed above) accompanying the reaction. Q is usually expressed in MeV. 

The nuclear aircraft carrier USS Enterprise in 1964 had its crew members spell out Einstein s mass-energy equivalence formula E = me2 on the flight deck. 

Hiroshima exploded with energy equivalent to about 20,000 tons of TNT.18 But where does all of this energy come from Unlike ordinary chemical reactions, nuclear fission does not involve breaking and forming chemical bonds. Instead, the energy comes from the loss of mass that accompanies the fission reaction. Most, if not all, of the students will be familiar with Einstein s famous equation, E = me2, but few are likely to understand what it means.19 In 1939, Lise Meitner and her nephew Robert Frisch reported their discovery of nuclear fission.20 They realized that the energy that accompanied the fission of uranium nuclei could be accounted for by using Einstein s equation. 

In nuclear physics and chemistry the masses of particles are often quoted as their energy equivalents (usually in megaelectronvolts). The unified atomic mass unit corresponds to 931.494 32 (28) MeV [70]. 

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