# Does the mass of photon affect its size or vice-versa?

Does the wavelength of photon affect its size, as when the wavelength is big the photon has big size and it small it has small size?

In the electron microscope the electron should poses a small wavelength, does the wavelength of electron affect also on its size? I know when the electron accelerate its mass increase due to its velocity but its wavelength is small how it can penetrate the bodies and form a more qualified image than photon if it has more mass and thus it will have a big size, is there any relation between the wavelength and the size of both electron and photon ?

## 3 Answers

Does the wavelength of photon affect on it's size as when the wavelength is big the photon has big size and it small it has small size??

No, photons are point particles in the standard model of particle physics, a quantum mechanical model. They have zero mass and energy equal to $h*ν$, where ν is the frequency of the classical wave that will be built up from a large number of the same energy photons. Here is a record of single photons , they have the footprint of a point in the detecting plane.

What the wavelength does is define the probability of detecting the photon, so accumulated measurements under same boundary conditions are needed to see the wave nature of a photon.

In the electronmicroscope the electron should poses a small wavelength ,does the wavelength of electron affect also on its size ?

Again, for quantum entities as the elementary particles, no size exists. For an electron it is the de broglie wavelength,

dependent on the electron momentum, which will control the probability of measuring the electron at an (x,y,z) at time t. It is the probability that may show wave effects, depending on the boundary conditions.

and I know when the electron accelerate its mass increase due to its velocity

This is a misconception, the mass you are describing is the relativistic mass and is not to be used in the de Broglie formula. The momentum there is with the invariant mass which does not change with energy as the name says.

but it's wavelength is small how it can penetrate the bodies and form a more qualified image than photon if it has more mass and thusit will have a big size

No, the size of the electron is always a point, what changes with momentum is the probability of interacting with the atoms and molecules under observation. The higher the energy the smaller the wavelength and accumulation of electrons will show the probability of scattering from the lattices under examination, which will depend on the wavelength.

is there any relation between the wavelength and the size of both electron and photon ?

No, see above.

No, there is no relation between the size of the photon or electron and the wavelength. Wavelength is not at all related to the size. The photon is massless. Does that mean light has no wavelength? Wavelength and size are not connected.

• According to you have said that the photon doesn't have size why there is a difference between photons on penetration the objects. And what about the wavelength is equal half the diameter of a sphear. – محمود Jan 17 '18 at 19:21
• I couldn't understand what you meant. Can you be a bit clearer? – Wrichik Basu Jan 17 '18 at 19:23
• I read on wikepedia that The electron is an elementary particle and has a classical radius . I mean that there is should be a size for a photon and electron acorrding to their diameter and radius that can be calculated from the wavelength. If there is any wrong information I said please told me the right answer. .thanks very much – محمود Jan 17 '18 at 19:26
• Yes, that is wrong. As per current observations through quantum mechanics, photons are massless and dimensionless. Electrons do have mass, but there is nothing called size - all these particles are dimensionless. It's a bit awkward to think like this, but that's the truth - all these particles are dimensionless and have no "size". – Wrichik Basu Jan 17 '18 at 19:35

A photon like any elementary particle doesn't have any "size".

Added further explanation: According to our present knowledge, all elementary particles, quarks, leptons, bosons, etc., including the photon, do not possess any property called "size". Thus there cannot be any influence of the wavelength of a photon on its size, because such a size does't exist.

• This is a comment, not an answer. – garyp Jan 17 '18 at 19:12
• @garyp - Thank you, I thought that the answer was obvious. If an object doesn't have the property "size" then also other properties of the object cannot have an influence on this non-existing property. I will add this to the answer. – freecharly Jan 17 '18 at 19:22