The tag has no wiki summary.

learn more… | top users | synonyms

0
votes
0answers
32 views

Why do different wavelengths travel at different speeds through a medium? [duplicate]

Someone gave an explanation in another question: "Maxwell's equations predict that in a linear medium with permittivity ϵ and permeability μ, the speed of light in the medium will be v=1/ϵμ. When ...
7
votes
2answers
883 views

How do we know the wavelength of colours?

Every site and video I have been on doesn't address it directly.specifically I want to know what is the evidence that we derive the wavelengths from and how do we calculate the wavelengths inspite of ...
1
vote
2answers
6k views

Frequency of the sound when blowing in a bottle

I'm sure you have tried sometime to make a sound by blowing in an empty bottle. Of course, the tone/frequency of the sound modifies if the bottle changes its shape, volume, etc. I am interested in ...
0
votes
1answer
40 views

Quantum properties of objects with zero velocity

Just curious: What would the Heisenberg Uncertainty Principle and De Broglie Wavelength be for a baseball that is not moving (i.e has zero velocity)? Also, since macroscopic objects like baseballs ...
27
votes
4answers
1k views

Are there any theoretical limits on the energy of a photon?

Is there any lower or upper limits on the energy of a photon? i.e. does the mathematical framework we currently use for Quantum Mechanics blow up when a photon surpasses a certain upper limit of ...
9
votes
2answers
179 views

Wavelength used in manufacturing of integrated circuits (IC)

How is it that the silicon ICs industry can burn ICs of a dozen nanometers using photolytography with UV laser of about 193 nanometers? Since the gates are smaller than the wavelength, for example ...
0
votes
1answer
29 views

Why EM waves with long wave length traveles long distance cmpared to EM waves of smaller wave length? [closed]

Most of the times i was told with an example that police uses red light because they travel large distance than compared to blue or green or other wave lengths ? ...
1
vote
1answer
33 views

If wave speed is dependent on medium only, then how to reconcile $v\propto f$?

I have read and learnt in many places that velocity of a wave depends only on the medium through which it travels. It is clear from this that the velocity of a wave doesn't depend on the frequency of ...
0
votes
1answer
34 views

How does a longer wavelength penetrate deeper with Rayleigh waves?

I'm struggling slightly to understand this idea. I've slowly been building up an explanation, so at this stage it might be just some confirmation I'm looking for, but also some guidance if I'm off ...
0
votes
1answer
21 views

Can a phase array evoke a standing wave at a focal point that has a much higher frequency that the constituent emitted frequencies?

This is a phased array: How can you focus sound? It can focus many waves of weak radio wave or light into a single focal point that's very strong. Now imagine that we delay half of the emitters by ...
0
votes
0answers
26 views

Ultrasonic cascade sonotrode design question

I wish to experiment with a cascade sonotrode =||<[]-[]==[[]]==[[]]==[[]].. <-something like this. -=||<[]- is the transducer. [large]=small=[large] (small and large diameters) Typically, ...
0
votes
0answers
24 views

What is the best laser wavelength to melt a certain material to the point of 'welding' together

Assume the material is enough of a heat sink that you can hold the torch to the material and the spread of the red-hot metal is not moving - is stabilized, but you can still melt the material in the ...
1
vote
3answers
61 views

How can frequency be constant during refraction? [duplicate]

When entering from a rarer to a denser medium, the speed of light decreases.I know that the frequency remains constant.But if frequency is cycles/sec then doesn't that mean more speed will lead to ...
1
vote
3answers
101 views

Relation between wavelength and system size

We always say that when a given light wave interacts with atoms bound in a molecule, only waves with wavelength close to the inter-atomic-spacing are able to probe the system. In other context ...
0
votes
1answer
41 views

Is there no way to create an arbitrary wave on a string fixed at two ends?

My question concern standing waves on a string with 2 fixed end. As there is one wave created, it will be reflected when it reaches one end and create another identical wave with opposite direction ...
1
vote
0answers
17 views

Minimum spread of frequency and wavelength in neodymium laser

What is the equation linking the minimum spread in wavelength and frequency of a pulsed laser, in relation to the lasers pulse time and operational wavelength. For example: If a Neodymium laser ...
0
votes
1answer
24 views

Question regarding frequency of pendulum while it is stopping

As a pendulum stops, the frequency increases, but of course the pendulum stops. So does the frequency increase so much that it... turns to 0? Or does this have to do with wavelength or speed?
1
vote
2answers
61 views

Do I need to convert units to be compatible with constants?

I want to calculate the wavelength of radiation given its energy. I know I need to use $E=h f$ and $f = c / \lambda$. All I'm given is $E = 20 \text{ keV}$, now my true question is: Do I use $E = ...
1
vote
0answers
22 views

Fresnel equations of reflection applied to microparticles

I wanted to know if the Fresnel equations of reflection, as described here, can be used to calculate the reflectance on the interface of particles which have a diameter near the size of the wavelength ...
0
votes
1answer
36 views

Error propagation from frequency to wavelength

I have measured a value for a frequency of $1.07 \times 10^{10} \pm 5 \times 10^7) \text{ Hz}$. Obviously it is very simple to find the wavelength from this frequency value, which I have (using ...
1
vote
0answers
25 views

Unusual waves and one of its parameter

I'm messing up with this java app on the web about waves on a string and i'm really curious about something. The java app is the following : ...
5
votes
2answers
848 views

Is the de Broglie wavelength of a photon equal to the EM wavelength of the radiation?

Is the de Broglie (matter) wavelength $\lambda=\frac{h}{p}$ of a photon equal to the electromagnetic wavelength of the radiation? I guess yes, but how come that photons have both a matter wave and an ...
1
vote
2answers
66 views

Is there a relation between music chords and visible light palette [closed]

Ok I have no idea if this is the right stackexchange so if you know who would know please tell me :) In music there are groups of notes that, when played togheter, are basis to harmony. Since both ...
9
votes
2answers
2k views

What is the minimum wavelength of electromagnetic radiation?

As a first approximation, I don't see how a wavelength of less than 2 Planck distances could exist. The question is: Are there any other limits that would come into play before that? For example: ...
53
votes
8answers
26k views

Why does a remote car key work when held to your head/body?

I was trying to unlock my car, but I was out of range. A friend of mine said that I have to hold the transmitter next to my head. It worked, so I tried the following later that day: Walked away from ...
2
votes
1answer
27 views

Question about wavelength of EM wave in dielectric

Many websites (http://maxwells-equations.com/materials/permittivity.php) lists out the following formula as to how you can compute the wavelength of an EM wave in a dielectric $$\lambda_d = ...
4
votes
2answers
136 views

Where does de Broglie wavelength $\lambda=h/p$ for massive particles come from?

I'm curious where the de Broglie relation $p=\frac{h}{\lambda}$ comes from? I know that for light (which has no rest mass), the following is true: $E=pc$ and $E=hf$ so, $$pc=hf \Rightarrow ...
0
votes
2answers
110 views

A simple quantum mechanics question [closed]

Here is the problem: Find the energy of neutron, electron and electromagnetic waves of wavelength 0.1nm. English is my second language, so I am kind of confused about the meaning of problem ...
1
vote
2answers
62 views

What is energy of light, as we know speed of light?

1.What is total energy of EM waves, as all got same speed? If two em waves has same energy, do they have same mass? If same mass and energy, do they have same frequency or wavelength still ...
2
votes
4answers
471 views

What was the motivation behind suggesting the trichromatic theory of vision?

Background In this thread, I asked whether it is true that the colors red, green and blue, through additive mixture, can make up any color. Turns out they can't. However, when reading about the ...
0
votes
3answers
276 views

Why frequency is inversely proportional to time-period?

Why frequency is inversely proportional to time-period? While studying about Fourier transform that shows frequency representation. A doubt that came to me was a set of signal with same wavelength ...
1
vote
3answers
80 views

Thought experiment about wavelength of light through a medium [duplicate]

Though the physical concepts and mathematics are highly rudimentary, I often try to comprehend exactly why light wants to keep it's frequency, yet alter it's wavelength as it travels through a medium, ...
0
votes
0answers
55 views

Relation between size of obstacle, wavelength and diffraction

"If the boundary is merely an obstacle implanted within the medium, and if the dimensions of the obstacle are smaller than the wavelength of the wave, then there will be very noticeable diffraction of ...
0
votes
0answers
26 views

Which wavelength of light can reflect easiest on any material?

What I know is, when wave has long wavelength it tend to penetrate matter. While a short wavelength tend to be absorbed So what is the medium value of wavelength has most probability to reflect? And ...
18
votes
7answers
14k views

What determines color — wavelength or frequency?

What determines the color of light -- is it the wavelength of the light or the frequency? (i.e. If you put light through a medium other than air, in order to keep its color the same, which one would ...
1
vote
2answers
76 views

What causes an increase in sound speed in a medium?

Its an established fact that increase in the temperature causes increase in speed of sound waves but what is the property which is changed by changing temperature ? Does frequency and wavelength get ...
1
vote
3answers
98 views

How damaging is light? [closed]

On Surely You're Joking Mr Feynman, when talking about the Trinity test, the author states: the only thing that could really hurt your eyes (bright light can never hurt your eyes) is ultraviolet ...
10
votes
3answers
51k views

Why does wavelength change as light enters a different medium?

When light waves enter a medium of higher refractive index than the previous, why is it that: Its wavelength decreases? The frequency of it has to stay the same?
0
votes
1answer
44 views

Propagation of sound waves and monopole

While it is understood that in order for the acoustic waves to reach far field the wavelength should be less than the characteristic length of the source, I am not able to physically understand how? ...
0
votes
1answer
73 views

Why do we perceive a colour?

White/yellow light hits a red case, and the red color is reflected into our eyes, since other wavelengths are absorbed. My question is: since both the paint on the case and the white light have ...
1
vote
1answer
72 views

What does the size of an object have to do with it's color?

Stephen Hawking mentions in his book 'A Brief History of Time' that quarks are much smaller than the wavelength of visible light so they do not have any color in the normal sense. What exactly does ...
1
vote
1answer
82 views

Police laser speed detection guns

Situation Police shooting a laser device into his rearview mirror, bouncing off the oncoming car license plate. I want to know if this second surface mirror, and the symmetric system--laser gun to ...
1
vote
3answers
111 views

Why does frequency increase as the length of an open air column shortens?

I am curious as to why the frequency of a wavelength increases as an open air column becomes smaller in length. Is it because an open air column will always contain half a wavelength, therefore if the ...
1
vote
2answers
40 views

Snells Law: Does the $k$ vector change on the boundary between mediums?

I was using Waves - Berkley Physics Volume III, and in explaining Snell's Law the author claims that as a wave is on the boundary between glass and air (going from glass to air) that the number of ...
5
votes
4answers
2k views

Radio antennas that are much shorter than the wavelength

From my limited experience with ham radio when I was a kid, I expect transmitting and receiving antennas to have lengths that are on the same order of magnitude as the wavelength, and in fact I recall ...
2
votes
1answer
523 views

Why doesn't De Broglie's wave equation work for photons?

Well, as I am learning about quantum physics, one of the first topics I came across was De Broglie's wave equation. $$\frac{h}{mc} = \lambda$$ As is obvious, it relates the wavelength to the mass of ...
14
votes
4answers
2k views

Is the frequency of light restricted?

What are the factors that limit the frequency of light? Can it have wavelengths ranging between zero and infinity?
4
votes
10answers
2k views

Why do we think of light as a wave?

I've read that light travels in a straight line and has a wavelength of 400nm to 700nm. But I don't understand why does it have a wavelength and what creates its wavelength? I agree with the concept ...
2
votes
1answer
35 views

Color in Different media

When a light wave passes from one medium to other, the wavelength of the light wave changes and the frequency remains constant. If then color of the light waves depends on changing wavelength or ...
23
votes
8answers
3k views

Why does wavelength affect diffraction?

I have seen many questions of this type but I could nowhere find the answer to "why". I know this is a phenomenon which has been seen and discovered and we know it happens and how it happens. But my ...