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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 ...
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0answers
17 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 ...
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2answers
29 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 ...
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1answer
25 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? ...
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1answer
57 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 ...
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1answer
65 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 ...
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3answers
45 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 ...
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3answers
84 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 ...
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4answers
1k 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?
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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 ...
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8answers
1k 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 ...
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1answer
31 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 ...
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1answer
65 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, ...
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1answer
70 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 ...
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2answers
58 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) ...
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1answer
344 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 ...
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3answers
99 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 ...
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0answers
40 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 ...
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2answers
38 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 ...
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3answers
79 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 ...
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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)
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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. ...
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1answer
207 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 ...
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1answer
229 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 ...
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1answer
166 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 ...
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0answers
27 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 ...
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2answers
166 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 ...
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1answer
456 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 ...
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8answers
15k 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 ...
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3answers
127 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 ...
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1answer
37 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 ...
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2answers
263 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
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4answers
326 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?
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1answer
89 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 ...
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0answers
74 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 ...
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1answer
74 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 ...
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1answer
725 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 ...
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2answers
248 views

Change in Wavelength of a Photon Relation to Energy (specifically Compton Effect)

Given a photon dropping from $\lambda_1$ to $\lambda_2$, its energy will drop from $\frac{hc}{(\lambda_1)}$ to $\frac{hc}{(\lambda_2)}$. However, I was wondering if there is any significance in the ...
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2answers
111 views

Diffraction pattern when wavelength tends to zero

While studying about Fresnel and Fraunhofer diffraction, I came across a statement which says that the fringes disappears and the image would take on the limiting shape of the aperture when wavelength ...
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0answers
88 views

Radar as range detector between cars-static sender vs dynamic sender

Say I have a radar transmitter on a car,used to detect its distance from a car in front of it by measuring the doppler shift on the reflected wave. i.e Car 1 is the source, its wave gets reflected by ...
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2answers
214 views

How is wavelength actually related to space (/distance)?

Is a photon of 400nm in wavelength "smaller" than a photon of 1km in wavelegth?
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1answer
62 views

Relationship between tones made by a piano

If a piano were to be tuned perfectly with the equal temperament system, what would be the relationship between standing waves from one note to the next? How would the frequency and wavelength of ...
0
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1answer
132 views

What is the wave length of the entire universe?

In quantum physics, particles are also waves. Larger particles have shorter wave lengths, and macroscopic objects have extremely short wave lengths so that the wave aspect can be ignored, and ...
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4answers
1k 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 ...
5
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1answer
699 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 ...
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0answers
50 views

How does QED deal with wavelength of quanta [duplicate]

Since QED treats photons as individual units (quanta) how does it treat the concept of the "wavelength" associated with the photon?
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2answers
3k views

De Broglie wavelength, frequency and velocity - interpretation

Two fundamental equations regarding wave-particle duality are: $$ \lambda = \frac{h}{p}, \\ \nu = E/h .$$ We talk about de Broglie wavelength, is it meaningful to talk about de Broglie frequency ...
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1answer
586 views

Finding the wavelength of an electron in its ground state?

To find the wavelength of an electron in its ground state in a hydrogen atom, would I or could I do the following? Use the ground state energy (-13.6eV) in $E^2 = m^2c^4 + p^2c^2$ Solve for $p$ Use ...
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1answer
239 views

Understanding de Broglie Wavelengths

I understand the derivation and calculation of de Broglie wavelengths, but what exactly does the wave of a particle represent? What does the wavelength of a particle mean? I'm assuming it's not the ...
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2answers
782 views

How does the wavelength change in relativistic limit?

In the text, it reads that the momentum of a particle will change if it is moving at speed close to light speed. In the general case, the wavelength is given as $$ \lambda = \frac{h}{p} $$ and $$p ...