Mass of the photon depends on the frequency?

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SUMMARY

The discussion centers on the misconception regarding the mass of photons, specifically whether it depends on frequency. Participants clarify that photons are massless particles, with their energy defined by the equation E=hv, where h is Planck's constant and v is frequency. The assertion that a photon has mass proportional to its frequency is incorrect; energy and mass are related but do not imply that increased energy results in increased mass for massless particles like photons. The correct relationship is encapsulated in the equation E² = (mc²)² + (pc)², where p represents momentum.

PREREQUISITES
  • Understanding of quantum mechanics concepts, particularly the nature of photons.
  • Familiarity with the equations E=hv and E² = (mc²)² + (pc)².
  • Knowledge of Planck's constant and its role in quantum physics.
  • Basic grasp of the principles of energy-mass equivalence.
NEXT STEPS
  • Study the implications of massless particles in quantum mechanics.
  • Explore the concept of energy-momentum relation in special relativity.
  • Investigate the role of Planck's constant in quantum physics.
  • Review experimental evidence regarding photon behavior and properties.
USEFUL FOR

Students of physics, particularly those studying quantum mechanics and special relativity, as well as educators seeking to clarify misconceptions about photon mass and energy.

hazim
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Mass of the photon depends on the frequency??

Hi all,

I'm 4th year electronics engineering student and so my question is curiosity.. We have taught that the photon has no mass, or its mass is zero. They even (the teachers and instructors) say that its mass is not negligible, but it is ZERO. This is for me not logical answer, it is a particle, then it must have a real mass even if this mass is 10^-99999999999Kg!

We have the energy of the photon E=hv, and we have E=mc2

E=E
hv=mc2

this means that m(photon)=hv/c2;
h/c2 is constant and the only variable is the frequency or the wavelength

This means that a photon with high frequency (which has higher energy) has more mass.

The mass of the photon (at a certain frequency) times c2 gives us it's energy (it looks similar to the kinetic energy of a moving mass).

A photon at rest or with no frequency does not exist, and therefore the rest mass is zero is only something theoretical...

And according to my view about the mass of the photon, if one substitute some different values of an electromagnetic wave, he will get logical values for the mass.

For example,
7.36 x 10-51 is h/c2
for a 1MHz frequency, the mass of the photon will be about 7.36 x 10-45 which is logical since it is much less than the mass of an electron.

In dialectical materialism and as the science proved, the energy doesn't vanish. And here I mean by energy both m and E which are in unity. So if we considered the energy E to be a mass of photons (and for example, also phonon for heat energy..), the mass itself would be in unity and the energy becomes only a theoretical explanation of the mass energy particles.

Awaiting for your views...

Hazim
 
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No E is not equal to mc^2 in general, the most general formula is

E^2 = (mc^2)^2 + (pc)^2

where p is the momentum and m the rest mass.
 


hazim said:
Hi all,

I'm 4th year electronics engineering student and so my question is curiosity.. We have taught that the photon has no mass, or its mass is zero. They even (the teachers and instructors) say that its mass is not negligible, but it is ZERO. This is for me not logical answer, it is a particle, then it must have a real mass even if this mass is 10^-99999999999Kg!
Then you have an incorrect idea of "particle". The physics definition of particle does not require that it have mass.

We have the energy of the photon E=hv, and we have E=mc2

E=E
hv=mc2

this means that m(photon)=hv/c2;
h/c2 is constant and the only variable is the frequency or the wavelength

This means that a photon with high frequency (which has higher energy) has more mass.
More energy, yes. That does NOT imply "more mass"

The mass of the photon (at a certain frequency) times c2 gives us it's energy (it looks similar to the kinetic energy of a moving mass).

A photon at rest or with no frequency does not exist, and therefore the rest mass is zero is only something theoretical...

And according to my view about the mass of the photon, if one substitute some different values of an electromagnetic wave, he will get logical values for the mass.

For example,
7.36 x 10-51 is h/c2
for a 1MHz frequency, the mass of the photon will be about 7.36 x 10-45 which is logical since it is much less than the mass of an electron.

In dialectical materialism and as the science proved, the energy doesn't vanish. And here I mean by energy both m and E which are in unity. So if we considered the energy E to be a mass of photons (and for example, also phonon for heat energy..), the mass itself would be in unity and the energy becomes only a theoretical explanation of the mass energy particles.

Awaiting for your views...

Hazim
 


hazim said:
Hi all,

I'm 4th year electronics engineering student and so my question is curiosity.. We have taught that the photon has no mass, or its mass is zero. They even (the teachers and instructors) say that its mass is not negligible, but it is ZERO. This is for me not logical answer, it is a particle, then it must have a real mass even if this mass is 10^-99999999999Kg!

We have the energy of the photon E=hv, and we have E=mc2

E=E
hv=mc2

this means that m(photon)=hv/c2;
h/c2 is constant and the only variable is the frequency or the wavelength

This means that a photon with high frequency (which has higher energy) has more mass.

The mass of the photon (at a certain frequency) times c2 gives us it's energy (it looks similar to the kinetic energy of a moving mass).

A photon at rest or with no frequency does not exist, and therefore the rest mass is zero is only something theoretical...

And according to my view about the mass of the photon, if one substitute some different values of an electromagnetic wave, he will get logical values for the mass.

For example,
7.36 x 10-51 is h/c2
for a 1MHz frequency, the mass of the photon will be about 7.36 x 10-45 which is logical since it is much less than the mass of an electron.

In dialectical materialism and as the science proved, the energy doesn't vanish. And here I mean by energy both m and E which are in unity. So if we considered the energy E to be a mass of photons (and for example, also phonon for heat energy..), the mass itself would be in unity and the energy becomes only a theoretical explanation of the mass energy particles.

Awaiting for your views...

Hazim

You are strongly advised to read an entry in our FAQ in the General Physics forum. You should also not make such speculation without paying attention to experimental evidence. For example, you will have a whale of a time trying to reconcile your assertion with this result: A.A. Abdo et al., Nature v.462, p.331 (2009).

Zz.
 


HallsofIvy said:
More energy, yes. That does NOT imply "more mass"

More mass imply more energy right? Considering the energy being a mass (quantum particles having mass as I said before) means that more energy imply more mass...
I confess that I don't have a good awareness of quantum physics but this may be a start for me in this interesting field.
 


hazim said:
More mass imply more energy right? Considering the energy being a mass (quantum particles having mass as I said before) means that more energy imply more mass...

This is patently false and incorrect. You wouldn't make such an erroneous statement had you done a little bit of "homework", such as reading the FAQ.

Please make sure you review the PF Rules that you had already agreed to. It is one thing to want to learn about physics, which we encourage. It is another to not care about basic physics (especially when you've been given it) but continue to make speculatively and spectacularly wrong guess work. The latter is not permitted in this forum.

Zz.
 

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