wavelength = h/mv (1 Viewer)

Gay Captain

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guys we learn in Q2Q that matter has an associated wavelength given by
lambda = h/mv

but we also learn in Space that v is relative to your reference frame

so a 1kg object sitting on your desk there is stationary (or near-stationary, you have to use uncertainty principle really) as far as you're concerned

but to someone standing on the sun that object is hurtling through space at hundreds of kilometres per second

so what's its debroglie wavelength? :confused:
 

Kirjava

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Although I'm no expert on this by any means, I should think that an object's wavelength would be effected by relative velocity in the same way as momentum, kinetic energy and the all the rest would. Of course, if the object was travelling at significant fractions of c one would have to apply the relativistic correction for mass (and hence momentum), but the same goes for all the other quantities too.

I'm rather more familiar with the equation E = hv though (having not formally studied QTQ), which, when we note that E = sqr(p^2c^2 + m^2c^4) makes it clear that the object's mass is far more "weighted" in the equation than its momentum (especially at non-relativistic velocties). So for the most part that object on your desk would have approximately the same wavelength from your perspective and from the sun.
 

Js^-1

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E=hv ???
I know E=hf, and E=mv^2/r
But wtf is E= hv?
 

samwell

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so are u trying to argue that if we apply relativistic velocities De broglie's wavelength? i think every particle has its well defined de broglie's wavelength because even if we apply frames of reference we will learn that in an inertial frame of reference no mechanical experiments can be performed. so i think for an object stationery in the earth it always has a velocity relative to something. If this conclusion is not accurate can somebody argue against it.
 

Js^-1

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I think the De broglie waevelength is relative, just as velocity is relative. An object with a relatively greater momentum will have a shorter wavelength than one with a relatively lesser momentum. As the object approaches zero velocity, relative to you, its wavelength increases to infinity, relative to you.

At least, thats the way I see it. I could be wrong.
 

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