# Thread: What is the mass of a particle traveling at the speed of light whose de broglie wavelength is 0.57 nm?

1. ## What is the mass of a particle traveling at the speed of light whose de broglie wavelength is 0.57 nm? var addthis_config = {"data_track_clickback":false};

The answer is 3.9E-33 kg, I'm looking for a solution to this problem. Any help (formulas, step-by-step solutions) would be great!

2. If it's traveling at the speed of light, its rest mass is zero, such as a photon. It could also be a gluon, graviton, or approximately it could be a neutrino. But if you're looking for an answer that matches that number, it's the m in

E = mc^2

Use the formula that relates de Broglie wavelength to energy, and you can find the energy. Then you can find the "mass".

3. More generally

E^2 = (p^2 x c^2) + (m^2 x c^4)

where p is the momentum and equal to (h x omega)/2 * PI

h is plancks constant

as far as I remember

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