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Photons have zero rest mass, but at the speed at which they move ... always the speed of light ... they have momentum, energy, and mass. Photon energy = (h n) Kinetic energy = (1/2 m c2) = (h n) ===> mass = (2 h n / c2) Momentum =(m c) = (2 h n / c) (h = Planck's constant, n = frequency, c = speed of light)

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5mo ago

Photons have momentum because they have energy and move at the speed of light. In physics, momentum is related to an object's velocity and energy, rather than just its mass. Therefore, photons, despite being massless particles, can still have momentum.

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Q: How do photons have momentum if they dont have mass?
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Must a particle have non-zero rest mass in order to have momentum?

No, a particle can still have momentum even if its rest mass is zero. For example, photons have zero rest mass but they do have momentum due to their energy.


Do photons physically move or displace opsin molecules of rhodopsin and if so how do they do so since photons have nearly 0 mass do they use their mass or some type of energy transfer?

Photons have energy, therefore they have both mass, and momentum. (Note: They do have a "rest mass" or "invariant mass" of zero, which basically means that they can only move at the speed of light.) Photons of high energy (and high mass, and high momentum) can destroy molecules, or even atoms.


Does light from a flashlight have mass?

No, light does not have mass. Light is composed of particles called photons, which have no rest mass, but they do have momentum and energy.


Which atomic particle has no mass?

Photons and neutrinos dont have mass.


What doesn't have mass?

Light and other forms of electromagnetic radiation (photons) do not have mass, but they do carry energy and momentum.


Do photons have weight?

Photons do not have mass, so they do not have weight in the traditional sense. However, they do have momentum and energy, as they can transfer these properties when interacting with matter.


How do photons exert force if force is mass times acceleration and photons have no rest mass and travel at constant speed?

Photons carry momentum and energy, and when they are absorbed or reflected by an object, they transfer that momentum which results in a force. This transfer of momentum is what allows photons to exert a force on objects despite not having mass.


What are tiny bundles of electromagnetic radiation?

Tiny bundles of electromagnetic radiation are called photons. Photons are the basic unit or particle of light and carry energy and momentum. They have no mass and travel at the speed of light.


Is that true that the more energy of a photon the bigger the mass it possesses?

No, all photons have the same mass. Photons are massless (i.e. zero). All the energy in a photon is in its momentum, but increasing its momentum does not change it speed which is always "the speed of light". All massless particles always move at the speed of light.


Why do gamma rays have no mass at all?

Gamma rays have no mass because they are a form of electromagnetic radiation, which consists of massless particles called photons. Photons, including gamma rays, do not have rest mass, but they do have energy and momentum.


What gives electron their speed?

Photons that are absorbed by the electrons. Speed is changed by an exchange of momentum, which is equal to the mass times velocity (with regards to electrons, at least - photons are massless and their momentum works a bit differently.) Since electrons have such a tiny mass, it doesn't take much to make it go very, very fast.


Does electromagnetic radiation has mass and charge?

Electromagnetic radiation, such as visible light or radio waves, does not have mass since it consists of massless particles called photons. These photons do not have an electric charge either but can carry energy and momentum.