Can Photon Energy Be Equated to Kinetic and Potential Energy?

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The discussion revolves around the relationship between photon energy and kinetic/potential energy, questioning if a photon’s energy can be equated to these forms. It clarifies that a photon has an invariant mass of zero, leading to the conclusion that its total energy is kinetic. The conversation highlights the importance of understanding momentum, noting that it is not simply mass times velocity for massless particles like photons. The term "relativistic mass" is mentioned but is generally considered deprecated in favor of using "invariant mass" or "rest mass." The key takeaway is that while mass and energy are interrelated, the conventional definitions of mass must be applied carefully in the context of photons.
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If the energy of single photon of electromagnetic radiation is defined by its wavelength, could it also be set equal to its potential and kinetics?(I’m probably missing something)
Please check this statement:
attachment.php?attachmentid=23675&stc=1&d=1265947307.jpg

Where :
h is planks constant
f is frequency.
m0 is rest mass
M is the relativistic mass
v is velocity


If rest mass of electron is zero then mc2 is zero therefore the total energy must be all kinetic(right?).
The only way I could see the kinetic energy not being zero is if somehow the relativistic mass is not zero…or maybe I got it completely wrong…?

Thx in advance.
 

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The correct relativistic expression is:

E^2 = m_0^2 c^4 + p^2 c^2 = h^2 f^2
Where m_0 is the invariant mass, p is the momentum, and the rest are as you have them above.

The expression is general and applies for both massless and massive particles, but a photon has an invariant mass of 0.
 
thx for response.

even so. if p is mass times the velocity, again it comes down the mass or at least the variant mass not being equal to zero.
maybe I'm not looking at it the right way but the variant mass of a particle being defined as
attachment.php?attachmentid=23680&stc=1&d=1265993338.jpg

gives the value 0 devided by zero as v\rightarrow c and as m_0 \rightarrow 0.

i guess the reason for my confusion is that if mass and energy are the same thing in different forms there must be a mass equivalent for a photon(right?)
 

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manifested said:
even so. if p is mass times the velocity, again it comes down the mass or at least the variant mass not being equal to zero.
maybe I'm not looking at it the right way but the variant mass of a particle being defined as
attachment.php?attachmentid=23680&stc=1&d=1265993338.jpg

gives the value 0 devided by zero as v\rightarrow c and as m_0 \rightarrow 0.
Momentum is not mass times velocity in general. As you mention the formula you provided is not valid for photons. The general formula for momentum is de Broglie's formula:
p=\frac{h}{\lambda}
where \lambda is the wavelength.

Which applies for both massive and massless particles.


manifested said:
i guess the reason for my confusion is that if mass and energy are the same thing in different forms there must be a mass equivalent for a photon(right?)
The term you are looking for is "relativistic mass". As you note, it is nothing more than another name for the total energy. Because we already have a perfectly good name for energy this term is generally deprecated. Usually the unqualified word "mass" refers to the "invariant mass" or "rest mass", m_0, but I tend to always explicitly say which definition of mass I am using just to avoid confusion.
 
So I know that electrons are fundamental, there's no 'material' that makes them up, it's like talking about a colour itself rather than a car or a flower. Now protons and neutrons and quarks and whatever other stuff is there fundamentally, I want someone to kind of teach me these, I have a lot of questions that books might not give the answer in the way I understand. Thanks
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