# Relation between mass and wavelength

1. ### Misr

391
Hi,
Why are mass and wavelength are inversely proportional?

2. ### Dr Lots-o'watts

673
Are you refering to de Broglie's matter waves?

As Hawking said, physics' job is to ask how.

But briefly, interference effects can be observed with electron beams, but not with marbles, and the shorter the wavelength of anything, the more it acts like a particle.

3. ### Misr

391
ok I change my question .."how are mass and wavelength are inversely proportional? "

4. ### diazona

2,156
$$\lambda = \frac{h}{p}$$

5. ### Misr

391
Looks very helpful but what is "h" and what is "p" ?

6. ### Dickfore

h is a fundamental constant of nature and

$$p = \frac{m \, v}{\sqrt{1 - v^{2}/c^{2}}}$$

is the momentum of a particle with mass m moving at speed v and c is the limit speed with which any interaction can be transmitted and is another fundamental constant of nature.

7. ### Misr

391
oh ok got it Thanks very much