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Do photons weigh anything?
Light is composed of photons, so we could ask if the photon has mass. The answer is then definitely “no”: the photon is a massless particle. According to theory it has energy and momentum but no mass, and this is confirmed by experiment to within strict limits.
How does a photon have no mass?
Why do photons have no mass? In short, the special theory of relativity predicts that photons do not have mass simply because they travel at the speed of light. This is also backed up by the theory of quantum electrodynamics, which predicts that photons cannot have mass as a result of U(1) -gauge symmetry.
What is the mass of a photon particle?
Originally Answered: What mass do photons have? The photon’s rest mass is zero. The concept of the rest mass derives from special relativity. The rest mass is the mass of a particle (in our case the photon) as measured by an observer who sees the particle still and with zero speed.
Does time exist for a photon?
Photons do not experience time. From the perspective of a photon, there is no such thing as time. It’s emitted, and might exist for hundreds of trillions of years, but for the photon, there’s zero time elapsed between when it’s emitted and when it’s absorbed again.
What is the formula for energy of a photon?
A photon is characterized either by wavelength (λ) or an equivalent energy E. The energy of a photon is inversely proportional to the wavelength of a photon. The Photon energy formula is given by, Where. E = photon energy, h = Planck ’s constant (6.626×10−34 Js), c = speed of the light and. λ = wavelength of the light.
How do you calculate a photon?
To find the energy of a photon, multiply Planck ‘s constant by the speed of light, then divide by the photon’s wavelength.
How much energy does a single photon have?
The energy of a single photon of green light of a wavelength of 520 nm has an energy of 2.38 eV. You can use the photon energy calculator to further explore the relationship between the photon energy and its frequency or wavelength.
Does photon have mass?
Sometimes people like to say that the photon does have mass because a photon has energy E = hf where h is Planck ‘s constant and f is the frequency of the photon. Energy, they say, is equivalent to mass according to Einstein’s famous formula E = mc2. They also say that a photon has momentum, and momentum p is related to mass m by p = mv.