Dear Jamil Kooli

Note that the equation E=mc2 is only a convenient means to calculate the amount of energy contained in mass m. In this equation, c does not represent the velocity of the mass in space. It just so happens that to convert kilograms (kg, which is the unit of mass) to joules (J, which is the unit of energy), kilograms have to be multiplied by the square of a velocity.

It was calculated more than 100 years ago that multiplying kilograms by the square of the speed of light provides the exact amount of energy contained in its equivalent mass.

For example, the electron was calculated and measured to have a rest mass of exactly 9.10938188E-31 kg. Since the speed of light is 999792458 m/s, multiplying the rest mass of the electron by the square of this velocity will give 8.18710414E-14 joules.

You can also calculate the same amount of energy if instead of calculating it by converting its mass to joules, you calculate it from the known frequency of the energy of which this rest mass is made, which is 1.235589976E20 Hz.

If you multiply this frequency by Planck's constant, which is 6.62606876E-34, you will get 8.18710414E-14 joules, just as with the equation E=mc2.

Another method is to proceed with the Coulomb equation and the known electron Compton wavelength, which is λc=2.426310215E-12 m, as follows:

E=e2/2ε0αλc=8.187104136E-14 joules.

These are all simple equations that allow converting the mass of electron to joules in the first case, frequency of the electron rest mass energy to joules in the second case and the wavelength of the energy of the rest mass of the electron to joules.

The velocity of the electron needs to be calculated from its momentum energy equation. This is energy in addition to that of its invariant rest mass.

Best Regards, André

For the umpteenth time, in special relativity, the mass is invariant under Lorentz transformations, energy and momentum are components of a 4-vector and the relation between energy and momentum that's invariant under Lorentz transformations is E^2-|p|^2c^2=m^2c^4.

A Lorentz boost amounts to changing E to mc^2coshφ and |p|c to mc^2sinhφ, where tanhφ=|v|/c.

If m≠0 and real, the RHS is positive and a standard exercise amounts to finding the Lorentz transformation from the frame where the 4-vector is of the form (E,p_x,p_y,p_z) to the form (E,0,0,0); in which frame E^2=m^2c^4 E=mc^2, since m>0.

If m=0, we have E^2=|p|^2c^2E=|p|c.

The de Broglie relation between wavelength and momentum is λ=h/|p|, which is perfectly consistent with special relativity, since |p|=h|k| and E=hω. For massless particles, ω=c|k| and, for massive particles, ω^2 = |k|^2+(mc^2)/(hbar)^2.

The calculation of the wavelength is correct according to the formula but I find that it is the interpretation of the say wavelength which is not correct.

Maybe this will help:

Preprint The Compton Wavelength Is the True Matter Wavelength, Linked...

Cheers,

Rusty

George (Rusty) Boyd,

Many thanks.

It is E=mcc which perturbs the good explication of the de Broglie wavelength in fact E=mcc inverses the interpretation of this say wavelength of de Broglie.

Dear all,

E=mvc is the good formula for a particle with mass. But is this formula has been tested experimentally? My response is no! To test this formula people should determine experimentally the intrinsic energy of an electron. But till now this thing is not done. In fact people should detrmine λ for the electron. And should derive the correspondent v using the de Broglie equation v=h/mλ. To derive λ people should recour to the experimental results in muonic hydrogen an deuterium. But people don't uderstand these results! Determining the intrinsic energy of the electron should lead to a determining of the maximal energy of the electron. Which should be reach in the sun! And according to de Boglie equation the correspondent v should be about the speed of light. In fact E=mvc gives every thing for a particle with a mass so what is this E=mcc? and why Einstein equalise it with E=hf? I have the response! De Broglie should find a link between his λ and the Compton wavelength but he has not make it it is then a lacune for de Broglie equation. That is why Einstein understood this lacuna of de Broglie and profitate from it. Einstein equalises therefore E=mcc with E=hf? Till now this thing of Einstein don't let people to understand the good meaning of the λ of de Broglie. In fact what is the absolute meaning of λ? it is the wavelength of what? People say E=mcc is not to applicate for photons because they are massless. E=mvc should be use to estimate the energy of a particle at rest when v is near the speed of light which is v for an electron in the sun. It stay to applicate E=mcc for the energy of photons where m is the mass of a photon! Or an other solution considering E=mcc obsolete. For a particle with mass E=mvc where v