Electron mass, energy equivalent

Of course, Eq. (3) is valid for any particle. The question is Why is the speed of the photon there One may conjecture with DiMarzio [26] that there is a more fundamental meaning for c. In this context, Munera [27] explored the possibility of deriving the main predictions of STR from Newton s theory plus a postulate of mass-energy equivalence E = mK2. The value of the unknown constant K was obtained from the acceleration of electrons [28]. The numerical value is c within the limits of accuracy of the (large) experimental error. 

Pair production involves the complete disappearance of the incident photon and the creation of an electron and a positron. It occurs only at incident energies larger than 1.02 MeV since an electron pair has to be created. Using the Einstein mass—energy relation E = me2, in fact, one finds that one electron mass is equivalent to 0.51 MeV. Energy in excess of 1.02 MeV is converted to kinetic energy of the pair. The probability of pair production increases slowly with energy and above 4 MeV it is proportional to log E and Z2. 

The difference between the mass of an atom and the sum of the masses of its protons, neutrons, and electrons is called the mass defect. Relativity theory tells us that the loss in mass shows up as energy (heat) given off to the surroundings. Thus, the formation of gF is exothermic. Einstein s mass-energy equivalence relationship states that... 

Combining Einstein s famous equation for mass-energy equivalence E = nuP) with the equation for the energy of a photon (E = hv = hc/X), de BrogUe derived an equation for the wavelength of any particle of mass m— whether planet, baseball, or electron—moving at speed u ... 

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... 

Whether this concept can stand up under a rigorous psychological analysis has never been discussed, at least in the literature of theoretical physics. It may even be inconsistent with quantum mechanics in that the creation of a finite mass is equivalent to the creation of energy that, by the uncertainty principle, requires a finite time A2 A h. Thus the creation of an electron would require a time of the order 10 20 second. Higher order operations would take more time, and the divergences found in quantum field theory due to infinite series of creation operations would spread over an infinite time, and so be quite unphysical. 

Within the approximation of the effective mass, consideration of the field created by the condensed media is confined to substitution of the real electron mass by the effective mass. Precise calculation of the effective mass is equivalent to solution of the Schrodinger equation with the consideration of the field created by the medium, and, consequently, as noted before, is hardly possible. Thus, as far as the problem of electron tunneling is concerned, the effective mass must be considered as a phenomenological parameter. In the case of tunneling with the energy I of the order of 1-5 eV, the field created by the medium apparently increases considerably the probability of electron tunneling, and the effective mass of electron can be noticeably lower than the real mass. 

The calculated gain of energy equivalent to the loss of mass is called the binding energy of the atom (or nucleus, if it is being considered independently of the electrons in the shells). When the binding energy calculations are... 

A common practice among scientists reflects the relationship between mass and energy They express the mass of a particle in either traditional units (grams, for example) or the energy equivalent of that mass. For example, the mass of an electron can be expressed as 9.042 x 10 28 g or as 0.511 MeV. Similarly, the mass of a proton can be expressed either as 1.660 x 10 24 g or as 938.26 MeV, the energy equivalent of that mass. 

Conditions in the universe almost immediately after the big bang were not favorable for the formation of electrons. At that point in time, gamma rays, photons, and neutrinos had very large amounts of energy, much more than was needed to produce electrons. Instead, conditions favored the creation of much more massive particles with large energy equivalents. Among these particles were the muon and the proton. A muon (also known as a mu meson) is a much more massive relative of the electron. It has amass of 1.870 x 10"25 g, about 2,000 times that of an electron. A proton is even heavier, with a mass of about 1.660 x 10 24 g, nearly 3,000 times that of an electron. 

A particularly useful factor converts a given mass defect in atomic mass units to its energy equivalent in electron volts ... 

---