Answer on Mechanics | Relativity Question for mahroosh
In analyzing the motion of an elastic wave through a material medium,we often ignore the molecular structur of matter.when is this justified and when is it not? plzzz anx me ryt now.........
Everything is dependent on the ratio between wavelength L and crystal lattice constant a: if L much greater than distance between neighboring atoms of medium, we can ignore molecular structure of matter. But if wavelength is small (wave vector k is large) then we need to consider discrete structure of crystal lattice.