# Tag Info

3

A good question, you are right the frequency remains constant (unless you have Doppler effects due to relative movement, but that's not your question). For visible light, refraction properties are quite often in question and as such it make sense to speak in terms of wavelength. As you go even higher in "frequency", physicists start talking in keV and MeV ...

2

The solar spectrum looks like the image below. The yellow shaded curve is the observed spectrum at the top of the atmosphere while the red curve is what we get at ground level. The black line is a blackbody model of the sun (a pretty good approximation, just don't worry about the yellow curve peaking above the black line) (source) 940 nm occurs right ...

1

Most 1300-nm optical fiber systems use single-mode fiber. Most 850-nm optical fiber systems use multimode fiber. Therefore, typical 850-nm transmitters are designed to couple into multimode fiber. Coupling into multimode fiber only requires focussing the light down onto a spot about 50 um in diameter. Single-mode fiber, on the other hand, typically has a ...

0

Is there a minimum wavelength in a black body's radiation? No... Or rather: Yes, Zero. In this image from Wikipedia, it does seem that the curve is touching the x-axis rather than being an asymptote It's not. The curve approaches zero rather quickly. So, it's hard to illustrate.

2

First of all, $\lambda$ is the wavelength and already carries a unit of length. So when you define $K=\frac{1m}{\lambda}$, this quantity would be dimensionless. And as you say, this really would be the number of cycles in one meter. But this is not the definition of wavenumber. The wavenumber and also the frequency are a measure of cycles in space/time per ...

2

I wonder if a bunch of microwave questions that appeared here recently is related to an enlightening (as usual) recent what if by xkcd. The radiation used in microwave ovens is not resonant for water molecules and industrial microwave ovens use 915 MHz (probably, because larger cavities can produce more power). The frequency of 2.45 GHz is chosen because it ...

0

The wavelengths that microwaves use allows the waves to resonate with the water to heat it up, with the added value that they are easily blocked to prevent damage to objects outside of the machine.

4

The uncertainty principle limits our ability to determine the wavelength of a particle with infinite precision. At the same time, there is no fundamental reason why any two photons (even if generated by exactly the same process) should produce exactly the same wavelength; however, you can be sure that there will be plenty that are the same within the limits ...

-1

Surely you'd agree that all electrons and protons are $exactly$ the same (indistinguishable). Now consider a regular Hydrogen-1 isotope: A proton and an electron bound together. There's definitely more than just one of these atoms in the observable universe. Well then consider an electron floating around the $n=2$ shell of a Hydrogen-1 isotope, then ...

11

Sir Elderberry, Punk_Physicist and the Count Iblis have all given correct answers in principle. There are two phenomena (really thought experiment, rather than practical, devices) that one needs to heed. A finite measuring time $T$ can only resolve frequencies to within an uncertainty of the order of $1/T$. This is the reciprocal relationship between the ...

16

Formally there are an infinite number of different wavelenghts. However, any given physical system can only be found in a finite number of distinct physical states. To create a light source with a wavelength $\lambda$ that is well defined up to some resolution $\delta\lambda$, requires observing it within a system of size of the order of ...

7

I believe that currently, light in free space (i.e., not in a waveguide or a crystal or anything tricky) is believed to be able to have all values of frequency/wavelength/energy. As you say, it is continuous. There are highly speculative theories that perhaps this is not true "all the way down" but thus far we have no evidence that the wavelength spectrum is ...

22

Yes, there are an uncountable infinity of possible wavelengths of light. In general the frequency spectrum for Electromagnetic (e.g light, radio, etc) is continuous and thus between any two frequencies there are an uncountable infinity of possible frequencies (just as there are an uncountable number of numbers between 1 and 2). Two things to consider in ...

-3

no, eventually you will be reduced to a discrete indivisible quantum of energy you can use the equation e = hf where e is energy, f is the fequency (colour of the the light) anf h is plancks constant, to figure out what colour the light would be for a given energy so light is not a complete spectrum of all possible colours @sirelderberry, your answer ...

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