What is relativistic mass of photon?
The relativistic mass of a photon m = E/c^2 = hf/c^2 (where m is mass, E is energy, f is frequency of the photon, h is Planck’s constant and c is lightspeed) comprises both its gravitational mass and its inertial mass, which are the same, but which comply with two different Newtonian laws.
What is meant by relativistic mass?
relativistic mass, in the special theory of relativity, the mass that is assigned to a body in motion.
Why does photon have zero rest mass?
From the particle nature of light, we consider light to travel in the form of small packets of energy or quanta of energy. These small packets are called photons. The photons are said to be chargeless and massless particles that travel at the speed of light. So the rest mass of a photon is taken to be zero.
How are photons massless?
If there was a way (there isn’t; special relativity prohibits it) to observe a photon at rest, you would find it massless. All the relativistic mass of the photon comes from it’s energy. In particle physics when we say mass, we usually refer to the rest mass. This is why we usually say that photons are massless.
Does relativistic mass create gravity?
Energy density (“relativistic mass”) does contribute to gravity – and the fact that the object is moving at relativistic speeds does affect the space-time around it.
What is momentum of photon?
Photon is a type of elementary particle which has a zero rest mass and moves with a speed of light in the vacuum. Einstein explained the momentum (p) of a photon with the given formula. The energy and momentum of a photon are related by the equation. E = pc.
Do photons have rest energy?
The fact that momentum carries energy is even true in classical E & M where electromagnetic fields are involved. Since photons have zero rest mass then their energy is simply E = pc. The fact that light carries momentum is also verified by experiment.
Do photons have mass or momentum?
In short, even though photons have no mass, they still have momentum proportional to their energy, given by the formula p=E/c. 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 is transmission diffraction grating?
Transmission gratings are diffraction gratings which are used in transmission. This is in contrast to the more common reflection gratings, which reflect all incident light, as far it is not absorbed or scattered. Transmission gratings can be volume Bragg gratings or surface relief gratings.
What is the relativistic mass of a photon?
Probably k = 1, since we can take p = m v as the definition of the relativistic mass, and p = E / c for a photon. Show activity on this post.
How do you find the mass of a photon?
If you did want to assign a photon a relativistic mass, there is no other parameter that could determine the mass besides its energy E, and based on units the mass would then have to be of the form m = k E / c 2, where k is a unitless constant.
Is relativistic mass obsolete?
Relativistic mass is obsolete. See Why is there a controversy on whether mass increases with speed? . Therefore this is not a question that modern physicists would consider of interest.
Why do we use relativistic mass convention?
Furthermore, the usual motivation given for using the relativistic mass convention is that it lets you use Newton’s second law without modification, but Newton’s second law isn’t going to apply to a photon, no matter how hard you try.