# De Broglie wavelength

1. Dec 8, 2005

### QueenFisher

we were having a discussion about this in physics and my teacher mentioned a relationship between the formula and some angle (don't know which!) but it's not on the syllabus any more, i was wondering does anyone know anything about this?

cheers for the help

2. Dec 8, 2005

### Chi Meson

Was there by any chance some mention of the "Compton effect"? Or was it mentioned in terms of x-rays? Or perhaps electron diffraction?

The deBroglie wavelength is used in may advanced physics applications; you'd have to give us some kind of clue here.

3. Dec 9, 2005

### QueenFisher

well it must be something pretty simple as it's only AS level physics, it came up during a discussion about the photoelectric effect...

4. Dec 9, 2005

### Chi Meson

My guess is that your teacher was talking about the Compton effect in which a photon collides with an electron. such a collision demonstrates the momentum of the photon since the electron recoils with a change in momentum. The photon (an x-ray) scatters at an angle theta according to the following formula:
$$\lambda '- \lambda=(h/mc)(1-cos \theta)$$

the (h/mc) term is the "Compton wavelength" of the recoiling electron

Last edited: Dec 9, 2005