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### Deriving the function

Posted: Tue Oct 10, 2017 4:30 pm
I am uncertain how to derive the DeBroglie Equation from the E=mc^2 equaiton. Is it necessary to know how to derive this function?

### Re: Deriving the function

Posted: Tue Oct 10, 2017 4:46 pm
You do not need to know how to derive ay equations. On the test you will be given a formula sheet that will include the de Broglie equation.

### Re: Deriving the function

Posted: Wed Oct 11, 2017 10:28 am
Does de Broglie's equation apply to particles of matter as well as photons of electromagnetic radiation?

### Re: Deriving the function  [ENDORSED]

Posted: Fri Oct 13, 2017 4:46 pm
Yes, De Broglie's equation applies to everything that has momentum (so your particle must have mass and velocity).
I think it was derived by relating quantum mechanics to classical mechanics. So,
E = mc^2 and E = hf
E = mc^2 = hf **set equations equal to one another**
E = mc^2 = h(c/λ) **substitute for frequency **
mc = h/λ **cancel the c's**
λ = h/mc **rearrange**
λ = h/mv **since c is the speed of light, if we had to apply this equation to other things, c would just be the speed of that thing (v)**

### Re: Deriving the function

Posted: Fri Oct 13, 2017 6:10 pm
When is it necessary to use this functions again?

### Re: Deriving the function

Posted: Sat Oct 14, 2017 6:54 pm
Tatiana R Dis 3E wrote:When is it necessary to use this functions again?

The de Broglie equation is used to measure the wavelength of the ejected electron.