## De Broglie's equation [ENDORSED]

$c=\lambda v$

Athena L 1B
Posts: 59
Joined: Fri Sep 28, 2018 12:18 am

### De Broglie's equation

Is De Broglie's equation the one that cannot be used for photons because it only applies to things with mass?

Mukil_Pari_2I
Posts: 87
Joined: Fri Sep 28, 2018 12:29 am

### Re: De Broglie's equation  [ENDORSED]

Yes. De broglie's equation (lamba = h / p) is the equation that cannot be used for photons. However, c=lambda/v, E=hv, E = (hc)/lambda, and E=(1/2)mv^2 can all be used with light.

Yixiao Hu 3C
Posts: 45
Joined: Fri Sep 28, 2018 12:19 am

### Re: De Broglie's equation

you can only use v=h/p for things with matter, for p=mv. if you wanna use that equation for massless photons, you willl be unable to put any numbers for m

Jessica Castro 2H
Posts: 60
Joined: Fri Sep 28, 2018 12:29 am

### Re: De Broglie's equation

De Broglie's equation can only be used for particles with rest mass. Since photons are massless, this equation does not apply for light.

mbaker4E
Posts: 69
Joined: Fri Sep 28, 2018 12:26 am

### Re: De Broglie's equation

Since light always travels at the speed of constant c, light is never at rest and therefore has zero rest mass. This is why photons have no rest mass and De Broglie's equation cannot be used.

daniela3D
Posts: 19
Joined: Fri Sep 28, 2018 12:25 am

### Re: De Broglie's equation

Yes. De Broglie focuses on calculating the wavelength of an object of mass.
When solving wavelengths use: wavelength= h/mv

When solving wavelength of a light or photon use: (E=hv; c=wavelength*frequency; E=hc/wavelength)

Ahmed Mahmood 4D
Posts: 72
Joined: Fri Sep 28, 2018 12:28 am

### Re: De Broglie's equation

Yes. De Broglie's equation is the equation that can be applied to objects w/ mass (Such as base balls and people) to determine their wavelength.