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### Photons?

Posted: Thu Nov 09, 2017 12:40 pm
Is the DeBroglie Equation only applicable to non-photon objects? Are photons the fastest particle ever?

### Re: Photons?

Posted: Thu Nov 09, 2017 12:58 pm
Yes and Yes

As discussed in my Wednesday review session the DeBroglie Equation applies to particles with rest/real mass that are moving.

You can also discuss this today (Thursday) in the many support hours I have organized:

Chemistry & Biochemistry, 4222 Young Hall
Victoria Ford 12-1 pm, Ronald Yang 12-1 pm, Karen Leung 1-2pm

STEM Learning Center, Boelter Science & Engineering Library 8251
Franklin Liu 2-4 pm

Five (physical) hours available today (Thursday), in addition to Chemistry Community.

### Re: Photons?

Posted: Thu Nov 09, 2017 1:55 pm
Yes, so if you are trying to find the wavelength of an ejected electron, you must use the De Brogile equation an its momentum. You cannot use E = hv and other extensions of it.

### Re: Photons?

Posted: Fri Apr 20, 2018 7:12 pm
I'm unclear on why E=h/p can't be used for photons. After all, photons do have momentum p and E=h/p is derived from equations that describe photons, so why doesn't E=h/p also describe photons? Photons don't have mass but they do have momentum, so I don't see why E=h/p can't be used for photons. I'm pretty sure the answer has to do with E=mc^2, but I'm having trouble making the connection. Please help. Thanks

### Re: Photons?  [ENDORSED]

Posted: Sat Apr 21, 2018 3:27 pm
Photons do not have a REST mass, which is another criteria for the equation to stand. Although a photon may have p, because they don't have a rest mass they do not apply to the De Broglie equation.