The tag has no wiki summary.

learn more… | top users | synonyms

1
vote
0answers
10 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
20 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
60 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
15 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
28 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
23 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 : ...
1
vote
2answers
52 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 ...
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 = ...
0
votes
2answers
79 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
61 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 ...
0
votes
3answers
146 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
72 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
37 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
22 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 ...
4
votes
2answers
127 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 ...
1
vote
2answers
46 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 ...
0
votes
1answer
36 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
60 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
80 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
82 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
3answers
95 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 ...
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?
2
votes
1answer
33 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
2k 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 ...
-1
votes
1answer
40 views

light color and refraction

I'm a bit confused on the topic of refraction, some starting premises: 1) When light refracts from exiting a medium with a low n and entering a medium with high n the light bends. 2) The index of ...
0
votes
1answer
135 views

Problem with plane mirror focal length thoery: Is the focal length actually infinite?

We all learned that the focal length of plane mirrors is considered to be infinite, as the radius of curvature is infinite. However, imagine this scenario: You have a perfectly flat (no one get mad, ...
1
vote
1answer
71 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 ...
2
votes
2answers
62 views

Why is water blue (on a quantum level)

OK, lets formulate it differently and say water works as a blue passing / red restricting filter. It is actually observable. Just do a dive in a swimming pool with white light (maybe even at night) ...
2
votes
1answer
432 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 ...
0
votes
3answers
105 views

Could this suggest that there is a wavelength smaller than Planck's?

Suppose the earth receives a photon with a wavelength $\gamma_1$. Since spacetime is expanding, we know that this photon had an original wavelength $\gamma_2$, such that $\gamma_2\lt\gamma_1$. This is ...
0
votes
0answers
59 views

Can temperature affect or change the wavelength or frequency of EMR?

If we were to emit Electro Magnetic Radiation(X-rays for example) to a very hot body such as the sun would we still get X-rays if we had a capturing device at the other end or would the high ...
1
vote
2answers
39 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 ...
0
votes
3answers
103 views

Compton Wavelength

I have the formula for Compton wavelength: $$\lambda_{c}= \frac{h}{m_{0}c}$$ In this equation, is $m_0$ the mass of the electron that the photon hit? I got online that this might be the photon rest ...
4
votes
2answers
1k views

What is the symbol Å?

I saw this symbol like: $$\lambda=3000\overset{\circ}{\text{A}}$$ and I don't know what this means. Is it a frequency? (since $\lambda$ is usually used for frequency)
1
vote
1answer
41 views

Diffraction, wave length

I read that when we want to study the structure of a crystal we have to use an electromagnetic wave which has a wave length of approximately the distance between two consecutive atoms in the crystal. ...
1
vote
1answer
279 views

Why does diffraction depend on wavelength? [closed]

We've all heard of the diffraction of radio waves over a mountain and the diffraction of water waves through a gap, but why does this effect depend on wavelength? I'm looking for as simple answer as ...
7
votes
1answer
314 views

Are small speakers inherently limited to higher frequencies?

I am hoping to build a subwoofer using multiple smaller speakers (165mm) instead of a single larger speaker (380mm). My theory is that the displaced air volume is what matters, not the individual ...
2
votes
1answer
188 views

Red color has largest wavelenght and violet minimum (in the range of visible light). then why does violet light appears reddish? RED + BLUE = VIOLET [duplicate]

My question is simple. Green light is more similar to red light than violet, then why is violet reddish and green not? in the language of frequencies and wavelengths, red and violet should contrast ...
0
votes
0answers
30 views

What is the perceived color of a D-illuminant?

I am implementing a software that simulates the color of the sky. To do this, I use a model that takes as input the sun position and returns the Yxy components of a D-illuminant for each point of the ...
0
votes
2answers
190 views

What is the reason behind why a quantum particle cannot be at rest?

So I've seen different reasonings for this; which is correct, or are they both corollaries of each other? 1) For a particle to be at rest, we would know its momentum and therefore by Heisenberg's ...
1
vote
1answer
734 views

Calculating the energy of an electron given the wavelength

Okay, so I know that the wavelength of an electron is 5e-7m and I am asked to calculate its minimum velocity and hence minimum energy. Calculating the minimum ...
53
votes
8answers
22k 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 ...
1
vote
3answers
156 views

Intuitive understanding of wavelength

Light is described as having wavelength. I can somewhat understand this in connection with for example the double slit experiment, that photons interact spatially in a wave like manner. But can the ...
0
votes
1answer
43 views

Resampling spectral data?

I want to use the CIE CMFs (Color Matching Functions) provided here: http://www.cvrl.org/cmfs.htm With data from my spectrometer in 10 nm increments. However, the CMFs are only provided at 5 nm ...
3
votes
2answers
327 views

Is the frequency/wavelength of light modified when multiple light sources are combined?

Let's say I light a wall with two spotlights: One red and one green one. Where they overlap, I'll see a yellow area at the wall. My question is, whether this is caused by an modification of the ...
7
votes
4answers
478 views

What {R,G,B} values would represent a 445nm monochrome lightsource color on a computer monitor?

Is it possible to answer my question definitely (assuming the monitor is perfect)? What would be the formula for calculating RGB values for a visible monochrome light with given wavelength?
0
votes
1answer
92 views

What does (simple) $j/cm^2$ represent AND how does this result $6.959j/cm^2$? [closed]

According to the image shown below, this specific Laser Hair Treatment device claims that it has a concentration of $6.959 j/cm^2$. So far by research I have found that it needs around $6\mbox{ to }7 ...
1
vote
0answers
81 views

Spreading UV light? Fresnel lenses?

I'm making a little UV exposure box and I'm looking for a way to evenly spread out the UV light. I've used Fresnel lenses to do just this in the past, but that was for visible light. But from what ...
1
vote
1answer
77 views

Too small error on the calculus of wavelenght

I have this function: $$\lambda=d \sin(\arctan(\frac{x}{z}))$$ and I want to find its absolute error. $d$ is a constant ($10^{-6}$), $x =(0.716 \pm 0.001)$ m, and $z=(1.000 \pm 0.001) $ m. For the ...
1
vote
1answer
880 views

What is limiting line in series spectrum?

The wavelength of first line in the Balmer Series is 'whatever(in nm)' . Calculate the wavelength of the second line and the 'limiting line' in the Balmer Series. I found this question in an ...