If photons have no mass,why do we call them ''light particles''?

Question

Can they be measured or weighted?

Answer 1

There is a heaven & hell difference between "Light"(opposite to heavy) and particles of light.
Photons are the particles of light.

There are concepts of "relative mass" and "resting mass" of photon which explains the nature of photon.

see this link dude...

http://math.ucr.edu/home/baez/physics/ParticleAndNuclear/photon_mass.html

Answer 2

A photon is the smallest particle of light. Light has a dual "wave -particle" behavior. Under certain observations(experiment) it behaves like a wave, under others it behaves as a particle. Mass is a property of a particle, not a requirement. In this respect, mass is similar to electric charge. A "particle" does not need electric charge to be observed exhibiting particle like behavior. Same with mass. Now a photon can transfer momentum and it can leave marks on a tv screen. In these ways it behaves as a particle.

Now, mass is a form of energy. And a photon has what we call no rest mass. Therefore, none of its energy is in the form of mass. If we measure the mass, we will obtain m=0

Answer 3

for those of you who think photons have mass....

The correct equation to calculate energy is

E = m x c^2 / (1-v^2/c^2)^.5

note that the velocity of a photon is c ( it travels at the speed of light) and what do you suppose E becomes if m is positive?

simplifying the above equation gives...
E^2 = c^2p^2 + m^2 c^4

for m = 0

E = cp where p is it's momentum = h x frequency / c
h, by the way, is plancks constant

in other words, the energy of a photon depends on its frequency not on it's mass (or lack of).

it's called a light particle because it has no mass and it behaves both as a particle and a wave.

see here....
http://en.wikipedia.org/wiki/Photons

Answer 4

Photons are the only particles which move with only one velocity unlike others which can move with any velocity staring from zero (at rest) to upper limit of the velocity of light. So other particles can be accelerated or decelerated but not light If you try to stop a photon it disappears. in other words its state of rest is an impossibility. But it does have energy. So it must have mass also as per the law of mass energy equivalence. Its mass is supposed to be hf/c^2. Now there is a formula which connect the mass of a moving object with its velocity, namely m=m'/sqrt[1-(v/c)^2], where m' is the rest mass. If we apply this formula to photon we would come to the conclusion that m' for photon would be zero. Thus photon can be considered as a particle having pure energy.

Answer 5

Think of the photon as a unit-package of light energy. That little package behaves as both a particle and a wave, and is described by quantum mechanics. Experiments show that the photon does not spread out as it propagates, and does not divide when it encounters a beam splitter. INstead, the photon acts like a point-like particle, and gets absorbed or emitted as a whole by systems much smaller than its wavelength, such as an electron.

Answer 6

Any moving thing which has kinetic energy is said to possess mass. ( Increase in mass).

Photons have increase in mass. Since the rest mass is zero the final mass is equal to the increase in mass.

We call them as light particles since they do possess increase in mass.

Yet they are not matters. Matters will have rest mass other than zero.

Since they do have increase in mass, they can be weighed.

Answer 7

gentle shows the phenomenon of interference, that's achievable in basic terms with waves. on the different hand gentle additionally shows the image-electric powered consequence, that demands gentle to be created from debris! no longer in basic terms those 2, yet there are countless different outcomes too, which point out the two in the direction of the wave-like, or in the direction of the particle-like properties of light. So, what quite gentle is? Wave or particle? This confusion over particle as against wave properties of light become resolved with the creation and employer of quantum mechanics interior the 1st a million/2 of the twentieth century, which finally defined wave-particle duality. It presented a single unified theoretical framework for information that each and absolutely everyone rely can behave in the two a wave-like and a particle-like vogue interior the suited circumstances. Quantum mechanics holds that each and each particle in nature, be it a photon, electron or atom, is defined by applying a answer to a differential equation, maximum ordinarily, the Schroedinger equation. The recommendations to this equation are huge-unfold as wave applications, as they're inherently wave-like of their form. they are able to diffract and interfere, best to the wave-like phenomena that are stated. yet additionally, the wave applications are interpreted as describing the risk of looking a particle at a given evaluate area. subsequently, if one is calling for a particle, one will locate one, with a danger density given by applying the sq. of the magnitude of the wave function. So, you possibly can end that we ought to evaluate the wave factor of light to describe a undeniable group of outcomes, and to evaluate the particle factor as a fashion to describe the the rest different group of outcomes. the two a kind of aspects are the two valid.

Answer 8

Photons have no rest mass - mass and energy are interchangeable as per E=Mc2, check out the special theory of relativity.

Answer 9

I asked my physics teacher once if photons were enrgy, or matter. She said "Yes".

They are energy, but act like matter, in that they can be deflected by gravitation fields. I don't know if they have mass though. I would have thought not.

Answer 10

They do have an "atomic mass", but they are called light particles because they are indeed what light is made of. As well as phonons and such.