# De broglie wavelength?

1. May 6, 2013

### Dammes

Before i understood that the de Broglie wavelength gets smaller as the momentum increases of an object, so my think was that because our (human body) momentum is so large that the de Broglie wavelength would be so small for there to be any effect on us, i know that we are also to large to undergo quantum affects. But if our wavelength is so small shouldn't we have high amount of energy, due to the formula E=hf?
Not sure if im getting the correct idea of what the de Broglie wavelength is?

2. May 7, 2013

### AnTiFreeze3

The de Broglie wavelength is simply the wavelength of a particle, but it happens to be immeasurable aside from when applied to elementary particles. A nice problem that demonstrates this:

This problem implies that particles can, in fact, possess the traits of waves, which in this case, is diffraction.

You obviously don't have to attempt this problem, but it does a great job of showing that de Broglie wavelengths are often undetectable, because the answer to this ends up being something around $1.5*10^{28}\mathrm m$. If someone has created equipment that can adequately follow these bullets, and measure their effects, well past Proxima Centauri (the closest star to our solar system), then I sure haven't heard of it.

Regarding your last question; $E=hf$ only applies to photons, so it doesn't make any sense to apply it to, say, a human being, which is where I think your confusion is coming from. If you're wanting to find the energy of a human, and have the momentum (with $p=mv$), it makes much more sense to find the kinetic energy through $KE={\frac{1}{2}}mv^2$.

I hope this helps