## wave property

$\lambda=\frac{h}{p}$

Julia Lee
Posts: 80
Joined: Fri Sep 28, 2018 12:29 am

### wave property

Hey guys,

So just to clarify, we cannot use the DeBroglie equation for light/photons since this is only applicable to things with resting mass?

anishathomas
Posts: 35
Joined: Fri Sep 28, 2018 12:25 am

### Re: wave property

Yeah photon's have zero mass and therefore you can't use that equation. Instead, you use the momentum to figure out the wavelength.

Posts: 74
Joined: Fri Sep 28, 2018 12:29 am

### Re: wave property

What do you mean by resting mass?

Raymond Ko 1H
Posts: 29
Joined: Fri Sep 28, 2018 12:19 am

### Re: wave property

Adriana_4H wrote:What do you mean by resting mass?

Resting mass means that when an object has no velocity (momentum), such as a vase sitting on a table or a book on a desk, the object has a mass that can be measured. Photons do not have measurable mass without momentum, meaning they have no resting mass.

Austin Clack
Posts: 29
Joined: Fri Sep 28, 2018 12:17 am

### Re: wave property

piggy backing off that last response... how is a photon's mass calculated when it does have momentum? If an object has no resting mass, does this mean it must have measurable mass taking momentum into account?