All Questions
Tagged with optics visible-light
1,367
questions
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Can the eye lens not produce a virtual image when the object is between Focus and Optical Centre?
My teacher dismissed the question saying it is not possible for the eye to do so simply because we didn't know the focal length of the eye. That confused me. The focal length can vary, sure. When we ...
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Does color temperature limit how much a laser of a given wavelength can heat a target?
The Sun has a peak wavelength of around 500 nm and an effective surface temperature of 5770 K, and sunlight cannot be focused to make something hotter than the Sun, because this would be heat flowing ...
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Solarization Spectrum
I'm looking to better understand the relation between the spectrum of the light which induces solarization in glass and the spectrum of the induced absorption.
More specifically, I'm interested in ...
- 1,538
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1
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47
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Directionality of laser light in vacuum [duplicate]
It is well-known that laser light is directional because of coherence from stimulated emission. This means that the light is emitted ONLY in the direction of propagation, and not in any type of ...
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1
answer
23
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Exit Pupil, Objective Aperture, Magnification, and Brightness
Why is it that for two pairs of binoculars, with equal aperture, the one with smaller magnification has larger exit pupil and results in brighter images? If I understand correctly, the aperture ...
2
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2
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102
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Why do gaps in my blinds create multiple lines?
Multiple lines appear on my floor every morning from the gaps in my blinds.
Why does this happen and does it have to do with light being a wave, like in the double slit experiment? If so could it be ...
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29
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Can the rainbow illustrate the colors we can’t see? [duplicate]
Seen as how we’re only able to see a relatively small portion of the electromagnetic spectrum, does the rainbow “keep going” in the frequencies we cannot see?
In other words; if we were able to see ...
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1
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Why does a ventilator appear to run leftwise and rightwise and back when spinning up?
My university professor, a friend of mine, asked me: "Do you know why, when a ventilator starts and during the process up to final speed, it runs clockwise and anticlockwise and back again to ...
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Is it possible to see thermal columns?
The most common way gliders gain altitude is to circle in a thermal. Thermals are often found below cumulus clouds, or above dark areas on the ground. Without these signs, they are harder to find and ...
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What exactly happens to a light ray that is incident on the vertex of 2 mirrors inclined at some angle
So the question I had was that if we have two mirrors as shown in the diagram, what exactly occurs to the light ray that is incident on the vertex of the mirror? If we would like to construct the ...
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How to determine if an observer can see an object with multiple mirrors?
How do I determine if an observer can see an object with multiple mirrors? I came across this image online and I am wondering if the observer (point O) see the object (point A)
My attempt:
I tried ...
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4
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A question about circularly polarized light
At work, a senior colleague thinks that circularly polarized light does not exist. My problem is that we both work on a project involving polarized light. In some occasions, I would like to point out ...
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1
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What is a convex-concave lens?
I came across this term while studying for optics, and I'm unsure as to what this means. My thinking is that it might be a meniscus lens, but the text separately give two different models for each ...
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1
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Pointing flash at LCD television creates a weird diffraction effect
I was looking around my room for something with my phone’s flash on, and noticed a very unique pattern reflecting off of the television.
FYI. The flash is white.
Any idea why it diffracts like that?
...
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How to measure light intensity in a room?
Does anyone know how I would go about measuring the light intensity in a room? I'm not interested in knowing the lux reading, I would like to measure the $W/m^2$ due to thermal radiation in my ...
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If a weak light source is attached to a string, and someone swing this light source in circle. It seems that this light source is brighter. Yes or no
It may be truly a question of life and death.
You know those glow sticks.
As a sailor it is a good idea to carry one on our lifevest.
Falling into the sea, those glow stick make a light source that ...
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Can the physics behind AR glasses be entirely modeled by geometric optics?
If I wanted to get the image of a small LED screen to be reflected onto the lens of a pair of glasses, would an understanding of geometric optics be sufficient to model this scenario?
I ask this ...
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General questions on the "big picture" of scalar diffraction theory
When studying diffraction, my courses at university stopped with frauenhofer diffraction, which - as far as I understand it - describes the diffracted far field for diffraction of a more or less ...
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1
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What will be the color of red laser pointer spot on green surface?
I have read this discussion
enter link description here
, yet I want to make things more clear.
In ideal conditions is it true that red laser pointer spot will appear on white sutrface as red while on ...
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1
answer
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Absorption spectra in films chemicals & dyes
For a science competition, we have to understand absorption spectra in films chemicals & dyes. But what is that? I've found resources on the absorption spectra of chlorophyll, but I'm unclear as ...
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Does quantum tunnelling have anything to with perception of light?
There have been studies suggesting that the sense of smell has something to do with quantum tunnelling but I'm afraid I don't know the exact details.
Do we possess internal mechanisms that simply &...
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Absorption and emission spectrum
I was wondering how do you see a spectrum when light is passed through a substance. Like most of the substances we use are opaque, so how does light pass through them without being reflected? Also ...
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Why does the energy (and thus frequency) of a photon entering glass stay constant if some is used up to accelerate electrons and slow down the light?
I'm learning optics and have been told that when light enters a medium (e.g. glass) and slows down the frequency of the light stays constant while it is the wavelength which is reduced. The ...
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Why is a bigger camera sensor better at low light than a smaller one?
People say a bigger camera sensor is better for light performance as the photo sensors are bigger and hence let in more light. But couldn't you just let the same light in and focus it down onto the ...
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Property of total internal reflection question
If I create a medium with gradually decreasing refractive index from once face at index 2.0 and other at 1.01, and show a beam of light upon the optically denser side, will there be any losses upon ...
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108
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Can the velocity of an image produced by a plane mirror be greater than that of light?
We are currently studying ray optics in school and it made me wonder if the velocity of an image produced by a plane mirror can theoretically be greater than that of light.
Using the relation $v_i = 2 ...
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Why in the experiment of double slits, in case of radiation of wavelength of red light, we can observe an envelop of the minimum?
I have made an experiment in which i have to measure the intensity of the light generated by an $\text{He-Ne}$ laser, in the case of two slits, I pretend to observe an interference lattice.
I have to ...
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1
answer
182
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Is there a way to determine whether what I see is a source of light, a real image, or a virtual image?
Let's suppose you are in a dark room and see something resembling a firefly. The light it emits is so dim that nothing else is visible. You're told that it's either a real source of light or an image ...
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Is there a way to calculate the angle between the refracted and reflected rays given the refractive index?
Is there a way to calculate the refracted and reflected rays? I know we use Snell's law to calculate the refracted rays, but is there a formula to calculate the angle of the reflected rays, or does it ...
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Apparent position of object in bowl of water
Say you have a bowl of water and you keep an object in it. What would the apparent position of an object inside the bowl from the position of an outside observer? Will the curvature of the spherical ...
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Any research or study that monitored the spectrum of the natural light during the entire day?
I am interested in understanding the light spectrum during sunrise, morning, midday, afternoon, golden hour, and blue hour.
Is there anyplace I can look at those?
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If a silver screen works for a movie projector then why not a mirror?
I have a projector and use a white sheet, thumb tacked, and stretched over a wall. It works fine. I went to the movie theater and looked at their screen closely. It was a fine silvery white glitter-...
user265090
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Could another star render color better than the Sun? If so, would a human be able to tell?
Disclaimer: This might be a better question for Worldbuilding SE, not completely sure.
I read today that the standard method of measuring color rendering index (CRI) is based on natural light (e.g. ...
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Is reflected photon the same? [duplicate]
When a single photon is reflected is the same one, or is it a new photon (emitted) while the 'original' photon has been absorbed?
I'm not sure how to imagine a refleced photon - it's not a ball ...
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Why do we see objects with a given color?
I'm currently studying Electromagnetic Optics, and I don't quite understand the (classical) process through which we perceive an object with a given color. From my understanding, I'd make a ...
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Why no image is formed when an incident and reflected ray intersect?
When two light rays intersect after reflecting from a concave mirror they form a real image.
but what happens if, say, a ray from the head of the object A collide with the reflected ray DA'? It might ...
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1
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Why do highlights occur on edges? [closed]
When looking at an object, the highlights are usually on the corners and edges. Highlights can occur anywhere on an object, but it seems like the brightest parts are where it is the most sharp.
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69
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Object and Image Distance from Image height, Object height, and focal length [closed]
Is there a way to find the object and image distances from the object height, image height, and focal length? I understand that the magnification is equal to $-\frac{d_i}{d_o}$ or $\frac{h_i}{h_o}$, ...
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1
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Physics behind Lambertian reflectors
Most ordinary surfaces are near Lambertian diffuse reflector, i.e. a small local radiates most strongly at norm then attenuates by cosine law when one gets to the tangentials. However this seems hard ...
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Minimum Radius of Curvature an Optical Fiber can be bent
Using the thickness and refractive index of an optical fiber, is it possible to know the maximum radius of curvature it can be bent before there are losses due to refraction?
In my research, I came ...
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2
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141
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Height of Mirror Required [duplicate]
I was curious about the minimum height of a mirror required to see your full body, and I found out that it was half of your height, in other words the minimum height to view the image = your height / ...
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Why is the $\cos^2$ envelope much more popular than $\cos^4$ to approximate the shape of a Gaussian laser pulse?
The Gaussian laser pulse
$$
E(t) = E_0 e^{\frac{-2\ln 2}{\tau^2} t^2} \cos{\omega t}
$$
(where $\tau$ is the intensity FWHM) is often troublesome in numerical simulations due to the infinite temporal ...
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Understanding and researching with Spectroscopy
I am very new to physics so don't know a whole lot yet, so please correct any incorrect vocabulary you may find. Papers that are easy for beginners to understand are also very welcome!
Context:
I am ...
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135
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Why diffraction works at sharp edges?
While introducing Diffraction, physics textbooks say that this effect (Diffraction) is observed distinctively when the light is passed through a very small opening, the length or diameter of which is ...
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What causes impossible colors (supergreen) that can be represented on a gamut to not be visible to the eye? [duplicate]
Supergreen is a color with an RGB value of (0, 255, 0), making it fully green, with no other colors. Now, according to my research, it is impossible for the human eye to detect this color. Doing ...
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When light passes from one medium to another. Depending on the density, it would experience a change in velocity. Why would its vector change as well?
For example, when light passes through water its velocity decreases and refraction occurs. Why? Why is there a change in direction. If I slow down a car I don’t suddenly turn left.
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1
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51
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What causes light to scatter in a medium?
My understanding is that all mediums have a complex iindex of refraction where the real component is the "standard" index of refraction, and the imaginary component is the extinction ...
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Fresnel Equations and an Opaque Surface?
I'm trying to make sense of what actually happens to light when it interacts with an opaque surface.
The fresnel equations give us the proportion of light which is reflected off the surface of a ...
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Why does white light appear white?
When I think of white light, I'm imagining a combination of all 7 colors of light but I believe that since light has wave nature I can say that at some point that the probability density of red light ...
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Calculating radiance
I'm trying to understand how to calculate radiance ($L_{e,\nu}$), so I am using the sun/earth as a comparison as I have seen it stated that the radiance of sunlight is equal to:
$$
L_{e,\Omega} \...
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