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When describing photons specifically rest mass is zero. The "rest mass" is the hypothetical mass a photon would have if it weren't moving at the speed of light, which as just stated, is zero. Nothing with a non-zero rest mass can travel at the speed of light in a vacuum, because it would require a literally infinite amount of energy to accelerate to that speed. (Neutrinos have a very small, but non-zero, rest mass, and therefore travel at most at slightly under the speed of light.)
What else can I help you with?
What is the difference between photons and electrons?
Photons have no charge, no rest mass and travel at the speed of light throuh a vacuum. Electrons have a charge of -1, have rest mass and are part of atoms.
What is the Difference between electrons and photons?
Photons have no charge, no rest mass and travel at the speed of light throuh a vacuum. Electrons have a charge of -1, have rest mass and are part of atoms.
What type of mass is light?
Light 'particles' (photons) have no rest mass.
Why the rest mass of photon is zero?
The rest mass of a photon is considered to be zero because photons are massless particles. They travel at the speed of light in a vacuum and do not possess rest mass. This is a fundamental property of photons in the Standard Model of particle physics.
Must a particle have non-zero rest mass in order to have momentum?
Yes. A particle of zero rest mass has ONLY its relativistic mass when in motion. There are actually no photons just sitting around.
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.
How do photons exert force if force is mass times acceleration and photons have no rest mass and travel at constant speed?
The problem in the posed question is the "mass" in the equation you quote is the mass of the object upon which the force (whether it be a photon or not) is acting, NOT the mass of the object exerting the force. You can MEASURE the net force on an object with mass simply by measuring the acceleration of that object and dividing it by the object's mass. Or you can predict an acceleration of an object with mass by calculating what its net force will be, and then dividing that by the object's mass. Unrelated to the above excellent answer, but another comment on the question: You mention, correctly, that photons have no rest-mass. But the photon is never at rest, and at the speed at which it moves from place to place, it has mass.
What things are have no mass?
Light, electromagnetic radiation, and energy itself are examples of things that have no mass. These entities are composed of particles that do not have rest mass, such as photons or gluons.
What is the differences between a w boson and a virtual photon?
W-bosons are charged and the photons are uncharged, W-bosons have a non zero rest mass and photons hsve zero rest mass. Also the W-boson is the "exchange particle" in interactions involving the weak nuclear force, but photons are the exchange particle of the electromagentic force.
How do you calculate the mass of light?
light has zero mass. Photons have zero mass. So according to e=mc2 light must also have zero energy. Astonishing how all these photons reach us from all the way across the universe! But all physical things have mass
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.
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.
