## What is the momentum of a massless particle?

zero

Massless particles travel at c In such a frame, the particle’s momentum p is zero by symmetry, since there is no preferred direction for it. Then E2=p2+m2 is zero as well, so the particle’s entire energy-momentum vector is zero.

## Do light photons have momentum?

Since light has no mass, you may be tempted to say that light has no momentum. However, light does indeed carry momentum in the form of energy. In fact, for photons (the smallest bits of light), the energy E and momentum p are related by the simple equation E = pc, where c is the speed of light.

**Can a photon have zero angular momentum?**

There is no value j = 0 for the photon: the wave function of a state with zero angular momentum must be spherically symmetrical, and this certainly cannot occur for a transverse wave.

**What is QCD theory?**

quantum chromodynamics (QCD), in physics, the theory that describes the action of the strong force. QCD was constructed in analogy to quantum electrodynamics (QED), the quantum field theory of the electromagnetic force.

### How are photons massless?

Since photons (particles of light) have no mass, they must obey E = pc and therefore get all of their energy from their momentum. But an object with zero energy and zero mass is nothing at all. Therefore, if an object with no mass is to physically exist, it can never be at rest. Such is the case with light.

### How does gravity affect massless particles?

Massless particles are known to experience the same gravitational acceleration as other particles (which provides empirical evidence for the equivalence principle) because they do have relativistic mass, which is what acts as the gravity charge.

**Why photon has no mass but has momentum?**

Note: Rest mass of photon is zero, whenever it starts moving with velocity C, it gains mass according to E= mc^2. Energy of moving particle converted into mass. That’s why its has momentum (when it start moving). Originally Answered: Photons are massless particles.

**How does a photon carry momentum?**

Particles carry momentum as well as energy. Despite photons having no mass, there has long been evidence that EM radiation carries momentum. Evidently, photons carry momentum in the direction of their motion (away from the Sun), and some of this momentum is transferred to dust particles in collisions.

#### Do massless particles have spin?

Massless particles and massive particles are both, well, matter! Given that spin is an intrinsic property of matter, the argument you imply (that spin should only apply to massive particles), is flawed.

#### Do photons have mass?

Since photons (particles of light) have no mass, they must obey E = pc and therefore get all of their energy from their momentum. But an object with zero energy and zero mass is nothing at all. Therefore, if an object with no mass is to physically exist, it can never be at rest.

**What is the difference between QED and QCD?**

QED stands for quantum electrodynamics where QCD stands for quantum chromodynamics. The key difference between QED and QCD is that QED describes the interactions of charged particles with the electromagnetic field, whereas QCD describes the interactions between quarks and gluons.

**How was quark gluon plasma discovered?**

Scientists at Brookhaven National Laboratory’s Relativistic Heavy Ion Collider announced they had created quark–gluon plasma by colliding gold ions at nearly the speed of light, reaching temperatures of 4 trillion degrees Celsius.

## Do massless photons have momentum?

As an explanation of why a large gravitational field (such as a black hole) can bend light, I have heard that light has momentum. This is given as a solution to the problem of only massive objects being affected by gravity. However, momentum is the product of mass and velocity, so, by this definition, massless photons cannot have momentum.

## What is the momentum of a photon?

Because photons have no mass, all of the momentum of a photon actually comes from its energy and frequency as described by the Planck-Einstein relation E=hf.

**What would happen to my spaceship if photons had mass?**

Your spaceship would be destroyed by all the trillions of photons hitting the ship on the pick up of the photon detector (the detector would be destroyed as well) if photons had mass. The momentum IS the energy. That energy has a mass equivalent but not as rest mass.

So we know photons have energy and travel at light speed, and they have momentum AND they are assigned a mass “of sorts” for the purpose of mathematical calculations. So why all the neigh saying about mass-bearing photons?

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