# Debroglie wavelength equation

1. Mar 22, 2013

### waterliyl

So for my AS specification I need to know how to use the debroile wavelength equation which is fair enough and easy.

I was wondering if anyone could tell me why do all particles have a wavelength or wave function? Or even like a tennis ball?

Thanks,

PS: I know it's a weird question, sorry!

2. Mar 22, 2013

### Staff: Mentor

Its not a silly question, but the answer probably isn't helpful either. All particles can be viewed as having a wave nature and as a consequence all things made of particles can be viewed as having a wave nature. This is the basis for Quantum Mechanics.

We can't explain why only that it is a testable fact of nature.

3. Mar 22, 2013

### Emilyjoint

Do you know how DeBroglie came up with his equation?....it is so simple but brilliant.
He knew that E = mc2 gave the energy equivalent of a particle and that E = hf = hc/λ gave the energy of a wave (photon) By equating these 2 equations he came up with the relationship mc = h/λ or momentum = h/λ. This gave the link between waves and particles that has been confirmed for all particles.

4. Mar 22, 2013

### Staff: Mentor

I think it was his PhD thesis paper and it was one page long. They almost didn't want to give him the degree.

5. Mar 24, 2013

### abhi1234

the original eqn which De-broglie took was E=[m^2c^4 +(pc)^2]^1/2.
He assumed m=0(i.e for photon),
What my ques is that , if he derived the equation for a photon ,than how can we apply this theory to any particle.

6. Mar 24, 2013

### Staff: Mentor

By not setting m=0

7. Mar 24, 2013

### Staff: Mentor

The typeset version I have is 109 pages long. Indeed, the evaluators (including Langevin) weren't sure what to make of it and passed on a copy to Einstein, who was positive about the work.