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I teach physics at Fullerton College, a community college in Southern California. I have an undergrad degree in math and physics from Berkeley and a PhD in physics from Yale. Back when I was doing research, my field was experimental low-energy nuclear physics.


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awarded  Good Question
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revised Producing photons with same frequency, different amplitude wave
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comment Producing photons with same frequency, different amplitude wave
This question has received some correct answers and some incorrect ones. The one that it's a duplicate of has an accepted answer that is correct.
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comment Which inertial observer should I choose when using $\Delta U = -\Delta K$?
If momentum is conserved for a system of particles, then energy is conserved in all frames of reference. If you simply posit a field of force acting on a single particle, then momentum is not conserved, and conservation of energy is not frame-independent.
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comment Relativistic Doppler Effect and the Sagnac effect
Why is it not the relative velocity of the receiver with respect to the photon itself? The velocity of light relative to anything is always the same. It's just $c$.
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comment Producing photons with same frequency, different amplitude wave
I am trying to give some justification to the common answer that all photons have the same A ... which is simply false, for the reasons given in my answer.
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comment Can light produce weak gravitational waves?
@CuriousOne: Unless somebody does the experiment there is no way of knowing. Not true. General relativity makes unequivocal predictions about this kind of thing, and it is a well tested theory. In particular, the gravitational fields made by light need not be weak, and we have direct evidence of this. The universe was radiation-dominated up until it was about 50,000 years old. This period includes the period of big-bang nucleosynthesis (BBN), so empirical data on BBN are a test of these cosmological models. Therefore we can confidently use GR to address this type of question.
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comment Producing photons with same frequency, different amplitude wave
"It" refers to the amplitude. When I said amplitudes are the same, I meant that in a vague sort of way because an individual doesn't even have a constant amplitude of course, as it is really described by a wave function, whose amplitudes are not even real numbers. So what do you think the magnitude of the amplitude is? But in a broad sense this amplitude (or the square of it) must integrate to 1. Right, which is not consistent with the amplitude being a fixed number for all photons of a given frequency.
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comment Underdetermined forces in a statics problem
@Michiel: Friction is a `response force' No, I don't think that's true. There is no such physical principle that I know of.
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revised Producing photons with same frequency, different amplitude wave
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answered Producing photons with same frequency, different amplitude wave
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comment Producing photons with same frequency, different amplitude wave
If you insist on thinking of photons as waves (which is fine of course), you can think of all of their amplitudes as being equal. Not true. If you think their amplitudes are all the same, what do you think it is?
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comment Producing photons with same frequency, different amplitude wave
This doesn't answer the question.
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comment Producing photons with same frequency, different amplitude wave
Two photons of the same frequency have the same "amplitude", No, their wavefunctions can differ.
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comment Is there any physical quantity that does not have uncertainty?
@CarlWitthoft: The uncertainty principle does not apply to counting the number of items (even photons). There is an uncertainty relation between number of quanta and phase for a harmonic oscillator: physics.stackexchange.com/questions/67929/…
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comment Is there any physical quantity that does not have uncertainty?
The OP is asking about quantum uncertainty, which is qualitatively different from uncertainty in measurements in general.
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revised Underdetermined forces in a statics problem
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comment Underdetermined forces in a statics problem
@dmckee: Even a small deviation will break the symmetry and make the system determined again. Hmm...I sketched an analysis, and it didn't look that way to me. In the asymmetric case, it seems to me that you have four unknowns ($N_1$, $N_2$, $F_1$, and $F_2$), and three equations: $F_x=0$, $F_y=0$, and $\tau=0$.
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awarded  Nice Question
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comment Underdetermined forces in a statics problem
@BMS: Yes, but in that example it's clear why it's underdetermined, and how the system knows what solution to pick: it picks the solution that's imposed by the externally determined force on the rope. Here there doesn't seem to be any such external force presently being exerted on the system that could determine which solution to pick.