### De Broglie's Equation

Posted:

**Sun Oct 13, 2019 7:47 pm**Why cant the De Broglie's equation be used for light?

Created by Dr. Laurence Lavelle

https://lavelle.chem.ucla.edu/forum/

https://lavelle.chem.ucla.edu/forum/viewtopic.php?f=18&t=47324

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Posted: **Sun Oct 13, 2019 7:47 pm**

Why cant the De Broglie's equation be used for light?

Posted: **Sun Oct 13, 2019 7:49 pm**

De Broglie's equation requires an object to have a mass, therefore, the equation cannot be used for light because light does not have a mass.

Posted: **Sun Oct 13, 2019 7:52 pm**

The photons have no mass. Keep in mind that there is a similar situation in which we cannot apply equations for electromagnetic radiation to electrons. For example, we cannot use c = lambda nu for problems involving properties of electrons.

Posted: **Sun Oct 13, 2019 7:53 pm**

De Broglie's equation is used for objects that has mass and behaves similarly to a wave. It also require momentum or velocity. Light theoretically doesn't have mass so the equation can't be used.

Posted: **Sun Oct 13, 2019 11:02 pm**

No, light cannot be used.

Posted: **Mon Oct 14, 2019 2:16 am**

The equation requires an object that has mass, but light does not have that. Thus, light cannot be used in this equation.

Posted: **Mon Oct 14, 2019 1:30 pm**

While all the previous replies have stated that light doesn't have mass and I agree, I just wanted to add that I remember Dr. Lavelle saying that the equation can only be used for particles with rest mass (mass at rest). It can be applied to everything else but light.

Posted: **Tue Oct 15, 2019 6:32 pm**

Light does not have mass, which is a required variable in the De Broglie equation.

Posted: **Tue Oct 15, 2019 8:14 pm**

De Broglie used light in order to derive the equation. The equation will work for any particle with momentum and it has a wavelength with its properties.

Posted: **Tue Oct 15, 2019 8:22 pm**

De Broglie suggested that the equation works for any particle with momentum, that has a rest mass, and has wavelike properties.

Posted: **Thu Oct 17, 2019 12:42 pm**

What is the difference between λ=h/p and c= λ*ν

Posted: **Thu Oct 17, 2019 12:56 pm**

The first equation you've listed is the De Broglie equation and that's used for electrons or objects that have a mass. You cannot use light with the De Broglie equation. The second equation you CAN use for photons (light).

Posted: **Thu Oct 17, 2019 2:19 pm**

De Broglie's equation requires an object to have a mass

wavelength = h/mv

wavelength = h/mv

Posted: **Fri Oct 18, 2019 11:35 am**

since wavelength=h/mv, the object must have a mass. While Light has a velocity, it does not have a mass to calculate

Posted: **Fri Oct 18, 2019 6:38 pm**

A photon does not have mass which is required for the de Broglie's equation where

Posted: **Sat Oct 19, 2019 8:57 am**

You need to have mass to use the De Broglie Equation, however photons of light do not have mass.

Posted: **Sat Oct 19, 2019 2:45 pm**

Photons don't have mass so the equation isn't applicable for it.

Posted: **Sun Oct 20, 2019 4:19 pm**

Photons do not have mass, only momentum.