Force verses energy

[jajrussel]

I would assume that if you bombard an object with photons that energy is exchanged? But, is a force exerted on the object? In the process? 
 

wondering if mass is needed to exert force and if so would relativistic mass be why photons exert  a force in objects?

Edited November 27, 2019 by jajrussel
Question expanded

[Strange]

Yes, light or photons will exert a force, for example: https://en.wikipedia.org/wiki/Solar_sail

This is because light has momentum, even if it doesn't have mass.

[jajrussel]

3 minutes ago, Strange said:

Yes, light or photons will exert a force, for example: https://en.wikipedia.org/wiki/Solar_sail

This is because light has momentum, even if it doesn't have mass.

Is momentum a property of relativistic mass, or is it the reverse, where relativistic mass is a property of momentum?

[Strange]

7 minutes ago, jajrussel said:

Is momentum a property of relativistic mass, or is it the reverse, where relativistic mass is a property of momentum?

Relativistic mass is just another way of describing energy (by relating the energy to mass using E=mc²).

In the case of photons, the momentum is an intrinsic property unrelated to mass. That is why the full mass-energy equation has two terms: one for mass and one for momentum: [math]E = \sqrt{ (m_0 c^2)^2 + (pc)^2 }[/math] (where m₀ is the rest mass and p is the momentum).

[jajrussel]

51 minutes ago, Strange said:

Relativistic mass is just another way of describing energy (by relating the energy to mass using E=mc²).

In the case of photons, the momentum is an intrinsic property unrelated to mass. That is why the full mass-energy equation has two terms: one for mass and one for momentum: E=(m0c2)2+(pc)2−−−−−−−−−−−−√ (where m₀ is the rest mass and p is the momentum).

Thank you . I need to think on this. It seems simple enough.. . I was wondering how, if it was all specific to momentum  one specific type of radiation would exert a greater force than any other radiation , since all travel at c.

as in a gamma ray burst has a momentum of c and the suns rays have a momentum of c then why would being in the path of a gamma ray burst be the greatest energy threat?  Was Thinking that there must be a scaler that indicates why two 0 mass particles at rest would have different forces at momentum c? is there something to the gamma ray photon particle that scales higher at c than there is to our suns everyday photon particle?

maybe you answered all my questions , and I just haven’t figured it out yet.

Edited November 27, 2019 by jajrussel

[Strange]

17 minutes ago, jajrussel said:

Thank you . I need to think on this. It seems simple enough.. . I was wondering how, if it was all specific to momentum  one specific type of radiation would exert a greater force than any other radiation , since all travel at c.

Ah, good question. That is the bit I left out!

The momentum and energy of a photon are related to its frequency (or, equivalently, wavelength).

So the momentum is [math]p = \frac{h\nu}{c} = \frac{h}{\lambda}[/math] (where [math]\nu[/math] is the frequency and [math]\lambda[/math] the wavelength). And energy is [math]E = p c[/math]

So gamma rays have more energy and more momentum because they are higher frequency (shorter wavelength).

[jajrussel]

1 minute ago, Strange said:

Ah, good question. That is the bit I left out!

The momentum and energy of a photon are related to its frequency (or, equivalently, wavelength).

So the momentum is p=hνc=hλ (where ν  is the frequency and λ the wavelength). And energy is E=pc

So gamma rays have more energy and more momentum because they are higher frequency (shorter wavelength).

Thank you... there was something I read that started me thinking about this, but I have forgotten what it was... 

so, if there is a scaler it isn’t related to c but to the initial energy value of the photon source that controls the wave frequency. Thus the energy/ force displayed during its interaction with another object? Is related to its initial creation energy?

note not trying to confuse. Just trying to communicate in a language I have difficulty understanding. So, sorry...

[Strange]

10 minutes ago, jajrussel said:

so, if there is a scaler it isn’t related to c but to the initial energy value of the photon source that controls the wave frequency. Thus the energy/ force displayed during its interaction with another object? Is related to its initial creation energy?

I think so (not sure what you mean by "scaler"?). For example, some photons are emitted by electrons going from a higher to a lower energy level in an atom. In that case the difference in energy between those levels defines the energy, and hence the frequency, of the photon. 

 

[jajrussel]

33 minutes ago, Strange said:

not sure what you mean by "scaler"?)

I assumed that in certain cases the force exerted would be a greater level and was wrongly trying to apply  it to c until  realized that c is c is c.... eventually  determining that since c is c  different values displayed as force on interaction must be due to the transmitting source.

initially I was wondering if by observing the result of two interacting particles you could determine the initial source of one of the particles,If you already knew something about the type of particle  that was acted on?At this point I am starting to confuse myself so I can only assume that I am confusing you. Once again thank you...

35 minutes ago, Strange said:

For example, some photons are emitted by electrons going from a higher to a lower energy level in an atom. In that case the difference in energy between those levels defines the energy, and hence the frequency, of the photon. 

Having nothing to do with the aforementioned scaler. Wouldn’t this on a universal scale lead to a very stable universe energy wise?

Edited November 27, 2019 by jajrussel

[swansont]

3 hours ago, jajrussel said:

Is momentum a property of relativistic mass, or is it the reverse, where relativistic mass is a property of momentum?

Momentum, like mass, is a property of a particle. They would not be properties of each other. 

A photon has momentum. An electron that's moving has momentum. And electron also has mass.

3 hours ago, jajrussel said:

  Was Thinking that there must be a scaler that indicates why two 0 mass particles at rest would have different forces at momentum c? 

0 mass particles are never at rest. They always move at c.

1 hour ago, jajrussel said:

 initially I was wondering if by observing the result of two interacting particles you could determine the initial source of one of the particles,If you already knew something about the type of particle  that was acted on?At this point I am starting to confuse myself so I can only assume that I am confusing you. Once again thank you...

Since energy and frequency are related, you can glean a certain amount of information by measuring one or the other. A photon at 1420 MHz probably came from a hyperfine transition in hydrogen, and if it's shifted a little from that, you could conclude that the source was moving relative to you. All atoms have characteristic spectra that are used this way.

[jajrussel]

46 minutes ago, swansont said:

A photon has momentum. An electron that's moving has momentum. And electron also has mass

46 minutes ago, swansont said:

Momentum, like mass, is a property of a particle. They would not be properties of each other. 

I see... Hopefully I will remember...  what about a particle determines its momentum if it is not initially a massless particle such as an electron? And when an electron changes orbitals it gives off a photon? Is the orbital shift completed at a certain momentum and is that momentum related to its mass?

and the orbital shift emitting a photon seems to suggest that very little energy is required to create a photon? Unless energy levels are determined by proportion? Just thinking here...

anyway thank you... I do have trouble figuring out what should be related to what. Property wise.

3 minutes ago, jajrussel said:

what about a particle determines its momentum if it is not initially a massless particle such as an electron?

I said this badly...How does an electrons mass determine its momentum? Does it?

Edited November 27, 2019 by jajrussel

[swansont]

11 minutes ago, jajrussel said:

I said this badly...How does an electrons mass determine its momentum? Does it?

Mass x velocity. p=mv (nonrelativistic formula)  You need to know both.

 

Quote

 

And when an electron changes orbitals it gives off a photon? Is the orbital shift completed at a certain momentum and is that momentum related to its mass?

and the orbital shift emitting a photon seems to suggest that very little energy is required to create a photon? Unless energy levels are determined by proportion? Just thinking here...

 

Talking about the momentum in an orbital is usually nonsensical. The whole atom has momentum, but you can't really assign a value to individual particles. They do not follow a classical trajectory.

The energy used to create the photon is the energy difference between the electron states.  That tells you its energy. There not used to make the photon (i.e. there's no waste involved). The only other energy would be the atomic recoil, and that's tiny for one photon — visible-energy photons cause a recoil of order 1 cm/s. The actual value depends on the exact energy and the atom's mass. (But scatter a few thousand photons and the effects are definitely noticeable)