Tagged Questions
14
votes
3answers
713 views
Amplitude of an electromagnetic wave containing a single photon
Given a light pulse in vacuum containing a single photon with an energy $E=h\nu$, what is the peak value of the electric / magnetic field?
1
vote
2answers
409 views
What is the formula for max kinetic and max potential energy of a spring?
What is the formula for max kinetic and max potential energy of a spring?
3
votes
2answers
946 views
The energy of an electromagnetic wave
The intensity of an electromagnetic wave is only related to its amplitude $E^2$ and not its frequency. A photon has the same wavelength as the wave that's carrying it, and its energy is $h f$.
So ...
24
votes
10answers
3k views
What happens to the energy when waves perfectly cancel each other?
What happens to the energy when waves perfectly cancel each other (destructive interference)? It appears that the energy "disappear" but the law of conservation of energy states that it can't be ...
4
votes
2answers
1k views
Physical interpretation of Parseval's theorem
I have read that Parseval's theorem, relating the norm of a function $f$ and the norm of its Fourier transform $g(k)$:
\begin{equation}
\int |f(x)|^2 dx=\int|g(k)|^2 dk
\end{equation}
has the ...
2
votes
2answers
176 views
Does EM radiation (any, i.e. RF), or sound, radiate everywhere at once?
I am having trouble understanding electromagnetic radiation (or waves in general, be it EM or sound). If I have a 1 Watt speaker, is it infinitely divided and spread out so that everyone in every ...
3
votes
2answers
337 views
Energy in an EM wave should depend on frequency
I just finished reading Feynman's Lectures on Physics vol.I, ยง34-9: "The momentum of light". The author explains that there is a relation between the wave 4-vector $k^{\mu}$ and the energy-momentum ...
3
votes
3answers
2k views
Why is energy in a wave proportional to amplitude squared
I'm a mathematics student trying to grasp some basics about wave propagation. A sentence I find very often in introductive physics textbooks is the following:
In a wave, energy is proportional to ...
2
votes
2answers
340 views
Does space have to be filled with charged particles to carry electromagnetic waves?
I'm a newbie here so have mercy.
I'm studying electromagnetic waves. This is the propagation of energy via the vibration of charged particles, as I understand it.
A charged particle could be like ...
