# What separates one particle from another?

JDude13
If each particle's wavefunction is directly related to it's energy (E=hv), how cn we tell the difference between a slow, heavy particle and a light, fast particle?

TriTertButoxy
The energy relation that you provided (E=hv) works only for massless particles, like the photon, which always moves at the speed of light. Therefore your question isn't quite consistent with the equation.

JDude13
Okay... umm... What is the equation for particles with mass? and is my question still valid?

What keeps particles with different types but simmilar levels of energy from being the same particle?

TriTertButoxy
oops, your equation is valid for all particle types. My mistake. I mistook your 'v' as somehow being related to velocity instead of the frequency.

Anyway, the answer to your question is that the momentum is different for particles of differing mass but with same energy.

Q-reeus
The energy relation that you provided (E=hv) works only for massless particles, like the photon, which always moves at the speed of light. Therefore your question isn't quite consistent with the equation...
..oops, your equation is valid for all particle types. My mistake. I mistook your 'v' as somehow being related to velocity instead of the frequency...
How do you come to that conclusion? This is confusing energy relations, which can be found by looking under the heading "The relativistic energy-momentum equation" at http://en.wikipedia.org/wiki/Mass_in_special_relativity, with the de Broglie relation p = hf/c (I here use f for frequency). There is a universal relationship between particle momentum p and frequency, not particle energy E and frequency!

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JDude13
oops, your equation is valid for all particle types. My mistake. I mistook your 'v' as somehow being related to velocity instead of the frequency.

Anyway, the answer to your question is that the momentum is different for particles of differing mass but with same energy.

But the equation doesn't say anything about momentum; just energy.

Could you please explain to me where momentum comes in?