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Answer the following questions: (e) Th...

Answer the following questions:
(e) The energy and momentum of an electron are related to the frequency and wavelength of the associated matter wave by the relations:
`E=hv, p=(h)/(lambda)`
But while the value of `lambda` is physically significant, the value of ν (and therefore, the value of the phase speed `νlambda`) has no physical significance. Why?

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The absolute value of energy E (but not momentum p) of any particle is arbitrary to within an additive constant. Hence, while `lambda` is physically significant, absolute value of ν of a matter wave of an electron has no direct physical meaning. The phase speed `vlambda` is likewise not physically significant. The group speed given by
`(dv)/(d(1//lambda))=(dE)/(dp)=(d)/(dp)((p^(2))/(2m))=(p)/(m)`
is physically meaningful.
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