# Number of photons in a given space

In summary, the conversation discusses the possibility of fitting an infinite number of massless photons into a small space. While it may seem theoretically possible, the Pauli exclusion principle and other physical laws make it impossible in reality. The classification of particles into fermions and bosons also plays a role in this discussion. The conversation also touches upon the topic of temperature and its effect on this concept.
Because they are massless, could you theoretically fit an infinite number of Photons into a small space? There is probably an equation that proves this wrong but I'm curious.

Because they are massless, could you theoretically fit an infinite number of Photons into a small space?
Hmm, I do not think so. Photons have energy, and if you stack a sufficiently (VERY) large number of them together into a sufficiently small space, according to physics a black hole should form. EDIT: Actually I'm not really sure about this at the moment, I have to think about it... EDIT 2: I have thought about it, and I think I am correct .

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I think the Pauli exclusion principle says that you can't have two particles having the same state in the same place at the same time,
Isn't that part of the definition of QM?

rootone said:
I think the Pauli exclusion principle says that you can't have two particles having the same state in the same place at the same time, Isn't that part of the definition of QM?
That's for fermions (they can't have the same state). Photons, however, are bosons. Particles are divided into fermions and bosons, see e.g.
Hyperphysics said:
Bosons are particles which have integer spin and which therefore are not constrained by the Pauli exclusion principle like the half-integer spin fermions.

sophiecentaur and rootone
Because they are massless, could you theoretically fit an infinite number of Photons into a small space? There is probably an equation that proves this wrong but I'm curious.

Whether or not an equation says it is possible, it obviously isn't possible in reality to set up a situation where you have an infinite number of photons in a finite amount of space.

## 1. How is the number of photons in a given space calculated?

The number of photons in a given space can be calculated by dividing the energy of the light source by the energy of a single photon. This will give you the number of photons present in that space.

## 2. Is the number of photons in a given space constant?

No, the number of photons in a given space can vary depending on the intensity of the light source and the size of the space. More intense light sources and larger spaces will have a higher number of photons.

## 3. Can the number of photons in a given space be measured?

Yes, the number of photons in a given space can be measured using specialized instruments such as a photometer or a spectrometer. These instruments can detect and measure the intensity of light, which can then be used to calculate the number of photons present.

## 4. How does the number of photons in a given space affect light intensity?

The number of photons in a given space directly affects the intensity of light. The more photons present, the more intense the light will be. This is because the energy of the photons adds up, resulting in a brighter light.

## 5. Can the number of photons in a given space change?

Yes, the number of photons in a given space can change. This can happen through various processes such as absorption, emission, or scattering of photons. The number of photons can also change if the intensity of the light source or the size of the space is altered.

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