Recent content by sirwan

what do you need to know about any element if you want to plot the spectrum of any element by that method.thanks.

thank you , I got some idea.

hello every one , I want to know how we get phonon frequency spectrum theoretically by using three modes and dispersion relation, can anyone explain it. for example it is phonon energy correspond to density of state how it is obtain?

what is the physical meaning of first pressure derivative of bulk modulus at zero pressure. if it is ∂k/∂p, i say how it change with pressure, if it is at zero pressure?

In solid crystal, according to Debye Model .why the frequency of vibration of one atom Different from one another? or why all atoms not vibrating with the same frequency. thanks

according to Einstein all atoms in solid vibrating with the same frequency , while in the Debye's mode there are a band of frequency i.e not all the atoms would have the same frequency, my question is that , that is the idea behind the Debye's model? or why the frequency of vibrating of atoms...

of course I mean the gravitational force ,why the moon does not orbit the sun? Is it relate to the difference of amount of gravitational force of each the sun and Earth to the moon or related to the different distance of the moon from sun and Earth ?

Which of them larger? The gravity of the Earth to the moon or the gravity of the sun to the moon?

we know that the total energy of the electron E=P^2 *C^2 + M^2*C^4 . M Is the rest mass of electron. when the rest mass of electron equal zero?

please. what is meaning by rest mass ? does mean its mass at zero velocity? does electron have zero velocity or it stop ?

does electron has rest mass?