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Gabriele Pinna
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The mass of a photon is zero but why does it have a momentum and an energy (E=mc^2=hv) ?
This is only true for objects at rest, and photons are not at rest.Gabriele Pinna said:E=mc^2
Gabriele Pinna said:The mass of a photon is zero but why does it have a momentum and an energy (E=mc^2=hv) ?
Gabriele Pinna said:But momentum is equal to p=mv so if m=0→p=0
Gabriele Pinna said:But momentum is equal to p=mv so if m=0→p=0
It sounds like something I would have said, but I have been silent in this thread so far.jtbell said:the "invariant mass / rest mass" which Orodruin is referring to.
And even for those, it is just an approximation for slow speeds.Drakkith said:That only applies to objects with mass.But momentum is equal to p=mv so if m=0→p=0
Gabriele Pinna said:But momentum is equal to p=mv so if m=0→p=0
A photon is a fundamental particle that is the basic unit of light and all other forms of electromagnetic radiation. It has no mass but carries energy and momentum.
According to Einstein's theory of relativity, mass and energy are two forms of the same thing. Since a photon has energy, it also has momentum, even though it has no mass.
The momentum of a photon can be calculated by multiplying its energy by the speed of light. This is known as the de Broglie equation, which relates the wavelength and frequency of a photon to its momentum.
Yes, the momentum of a photon can change when it interacts with matter. This can happen through processes such as absorption, emission, or scattering.
The fact that photons have momentum without mass is important in understanding the behavior of light and electromagnetic radiation. It also has applications in various fields such as optics, telecommunications, and quantum mechanics.