# What is White light: Definition and 70 Discussions

White Light/White Heat is the second studio album by American rock band the Velvet Underground, released in 1968 on Verve Records. It was the band's last studio recording of new material with bassist and founding member John Cale.

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1. ### Perceiving white light from Lightbulb Illumination

What is exactly hitting the retina for us to perceive white light in a room radiated by light from a lightbulb? The light from the lightbulb caused by heat radiates wavelengths randomly through the space around it. But how could it be that the superposition of these random frequencies and...
2. ### I Why don't red dwarf stars emit white light like the Sun?

Blackbody radiation spectra of hot light sources ( stars in this case) should have the full visible light spectrum and still stars less massive than the Sun emit reddish light while stars more massive than the Sun emit blue light. How is the blackbody radiation spectrum altered by the star mass?
3. ### How to concentrate white light in a very small point?

Good morning everyone. I have a question for the community. I am doing an optical project in which I need, as the title says, to concentrate white light in a very small point, with a diameter of the order of microns, so that I can pass light through a pinhole. I've been trying it with some lens...
4. ### White light interference pattern and its resolution criteria

Homework Statement Homework EquationsThe Attempt at a Solution I don't know how to do part d. For di, i know that separation of arm d should be small in order to have spatial coherence. For dii, what is the meaningful criterion, can I say the primary max of blue light lies on the first zero...
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### Diffraction Grating and White Light Problem

Homework Statement White light containing wavelengths from 400 nm to 750 nm falls on a grating with 6000 lines/cm. How wide is the first-order spectrum on a screen 2.0 meters away Homework Equations dsinθ=mλ for constructive interference dsinθ=(m+1/2)λ for destructive interference Δx = λL/d...
6. ### Optics : White light incident on water drop

1. Homework Statement Homework EquationsThe Attempt at a Solution [/B] I know that if white light is incident on a triangular prism , then lights of different wavelengths are deviated by different amounts and dispersion occurs . But I am not sure what would happen in this case where we have a...
7. ### Why Doesn't White Light Appear Green Despite Human Eye Sensitivity?

White light is usually stated as having a uniform spectrum (eg all frequencies at same intensity). However the human eye is more sensitive to green light than other colours. So why doesn't white light appear slightly green?
8. ### White light vs visible spectrum

Does white light contain only the wavelengths of visible spectrum (i.e only from 400nm to 800nm)?
9. ### Why does diffracted white light have a white central fringe?

Hey everybody, Homework Statement : [/B] I came across a question discussing Young's Double Slit interference and was wondering how come when we diffract white light through the slits it gives us a central antinodal fringe that is also white? The question itself came in parts firstly...
10. ### White light thru prism: Why aren't separated colors actually mixed?

Ok, here's the illustration of the experiment: http://media.web.britannica.com/eb-media/10/7710-050-36C066AC.jpg But if you trace the light path back from the prism and into the white light, it seems as though the white light is actually made up of STACKED colors of the rainbow, not a MIXTURE...
11. ### Understanding Starlight: White Light, Double Slit Experiment, and Color Emission

I've been recently watching videos about white light and the double slit experiment and how it creates a rainbow. It let me to some confusion and I would like some clarification. My questions are: Do all stars like ours produce white light? Would red giants only emit red light and blue giants...
12. ### Perceived Color of objects: in White light from a TV

Background: Normal white Sun light has a continuous spectrum in the whole of visible range. But, white light (rather what we perceive as white) coming out of a Monitor/TV is have only RGB in it and it looks white because of the Tricolor vision which excites all three types of cells in the eye...
13. ### Amount of single photons to make white light?

First off I hope I'm putting this in the correct forum. My question is more than just the minimum amount of photons to make a single blip of white light, but more so the base photons in the visible spectrum of light. We have all seen a prism split light into violet, blue, cyan, green, yellow...
14. ### Understanding the Nature of White Light: Coherency and Mixture Explained

Is White light a superposition(Interference) of different wavelengths(V,I,B,G,Y,O,R) ? Or is it a mixture of these wavelengths, i do not even properly know about mixtures but my sir told me that for mixture you do not need sources of these light(V,I,B,G,Y,O,R) to be COHERENT , so we can light up...
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### What was the mysterious bright light that appeared in my dark room?

I was walking into a dark room when a REALLY bright, like laser bright fist sized point of whitish blue light streaked in an irregular pattern just below the ceiling and vanished. It stopped me dead in my tracks startling me, it was moving VERY fast and disappeared within a couple seconds. It...
16. ### Optical microscopes and white light / laser light

I have a few questions regarding an optical microscope and their white light sources... So white light generally first hits a diffuser, some kind of ground glass lens. What is the purpose of this? Then the light goes through a field diaphragm, which we can open and close. I have heard that...
17. ### Bright light from white light connected 240ac through 1k

I have connected 4 White LEDs with 240ac main through 1K resistor in series. The brightness of the output is not satisfactory. What can i resolve this issue? Thanks
18. ### Can I Reach the End of a Rainbow with a Shovel?

I'm interested in rainbows. I'm talking about good old fashioned arc/halo rainbows like those you see in the sky. Sometimes you see rainbows from lawn sprinklers. How small would the smallest rainbow arc conceivably possible to view be? Could I make a rainbow at night using a sprinkler with a...
19. ### Where is fringe spacing measured from with white light?

Fringe spacing is the distance between two adjacent maxima or minima. For white light, is a maxima the distance from red to red (green to green, blue to blue..)? or the middle of the maxima to another middle of another maxima (i see that this distance will be the same since its middle to middle...
20. ### Prism -- brightness of a ray of white light as it passes through a prism?

What happens to the brightness of a ray of white light as it passes through a prism?
21. ### Unexpected white light interference pattern

Dear fellow Physicists, For my project I wanted to measure the thickness of a glass plate with white light interference. Before being able to measure, I had to setup an interferometer. Unlike with a Laser, with white light it is hard to find the interference pattern since the coherence length...
22. ### Problem about application of E = hv to white light

The reason why we see white light is because we see all the light in the visible lights spectrum. So let's say I have a light bulb that gives out white light, the reason why it gives out light its because it keeps emitting a constant amount of energy. By E = hv, we should only be able to see...
23. ### Calculating the Frequency of White Light

I am doing a research project on sonoluminescence and I want to measure the ratio between the frequency of the sound waves needed to create the cavitation bubble to the frequency of the light emitted. If I have the spectral lines of the light emitted, is there a way to measure the frequency of...
24. ### Does White Light Really Exist as One Wave?

White light is composed of 7 wavelengths. And yet we show white light as one single electrical wave perpendicular to the accompanying magnetic wave. Don't all the waves actually travel separate (though at the same speed)? Also, does polarization of light mean cutting out on the magnetic field...
25. ### Why does 'white light' from the Sun look yellow?

Light from the sun can be dispersed into its spectrum of colours. But when we look around us, and at the sun, it appears yellow. Then shouldn't it only be emitting the yellow part of the spectrum? We also use 'white light' sources when diffracting light through double slits, but then I couldn't...
26. ### Double Slit Experiment with White Light and one Slit colour filtered

What would happen if the double slit experiment were to be undertaken using white light, and one of the slits was covered by a monochromatic filter (i.e. something which only one wavelength could pass through), and apart from this there was no detector monitoring which slit each photon was...
27. ### Mirau White Light Interferometer. Light Source?

Hi everyone, I'm building a white light interferometer and need help choosing and finding a white light source. I'm using this mirau objective: http://www.edmundoptics.com/microscopy/infinity-corrected-objectives/nikon-interferometry-objectives/59312 Here is the setup: I know...
28. ### [Thin-Film Optics] Incident white light to color

Hello, as you might have guessed, my question revolves around thin film optics. My intention is: Given a two thin-film system residing on top of a semi-infinite (bulk) layer, how can I estimate the reflecting color (RGB preferably) when illuminated by white light? (Illustrated below). I...
29. ### Estimating Compound Color in White Light: Confused?

I have a question which asks me to estimate the color of a compound in white light. I can easily get the wavelength (hc/dE) as 460nm, which agrees with the book. Looking at a spectrum list that would seem to fall in the blue range, but the book is saying it would be orange because blue is...
30. ### Diffraction grating with monochromatic light vs. white light?

(A) What kind of pattern of would you get if you shone monochromatic light on a diffraction grating? What pattern of light would you get if you shone white light on a diffraction grating? My answer: With monochromatic light, you would get a pattern of alternating light and dark bands. With...
31. ### Why is it not possible to see the interference pattern of white light

'The colour seen when white light is used as a source for a Young’s double slit experiment are sometimes mistaken for the spectrum of visible light.' Why is this not possible with a two slit interference pattern? I know that the different wavelengths will all cause interference with each...
32. ### Collimating a white light beam

Dear all I need collimating light from a Xe arc source. More in details, the white light source is coupled to a monochromator. In fact I need a circular collimate light beam from the monochromator with a diameter of 1-2 mm. At the moment I am using a (rectangular) slit in the monochromator...
33. ### What Differentiates Bright Light from White Light in Human Perception?

What difference does our eyes detect when we see light, that our brain can differentiate between simply a whiteboard and the sun being reflected on a whiteboard? A whiteboard under normal circumstances looks white, yet when a bright light source is reflected on it, we notice it is not the same...
34. ### White light to different colors

Hi I have a question, when shining a flash light (white light) we are getting all the visible spectrum of light correct; the wavelengths are under 400 to above 700 nm ? now if we put a red or blue plastic sheet on top of the flash light we see the color of that plastic sheet. What is...
35. ### So when i see white light, is it really just seven different photons?

Im a little confused as to why the eye detects white light as white instead of all the separate colors that compose white light. I mean it isn't a single photon right (multiple single photons of course)? So how do the different photons converge into one color? Also, which may seem like a very...
36. ### Polarization of white light beam

I want to find out that what happens if we polarize a white light which has all of the wavelenghts of 400-700 (nm).Does it divide into colors?What happens to it?
37. ### How does white light combine different colors of the spectrum?

I have been thinking about white light and having some trouble visualising how it actually works. I am aware that white light is made up from all the colours of the visible spectrum, my question is how does the light travel together in wave and photon form? my only thoughts so far are that...
38. ### Ray tracing diagram for white light moving through glass

Homework Statement White light is incident on a sheet of glass as shown below. Complete the ray tracing diagram. Homework Equations n1(sinx)=n2(siny), where n = the refractive index of the medium. The Attempt at a Solution The ray on the bottom is hitting the glass at 90 degree angles...
39. ### How and why does a prism split white light into the colour spectrum

[Solved] How and why does a prism split white light into the colour spectrum Homework Statement How and why does a prism split white light into the colour spectrum? Homework Equations Red light has a lower frequency than violet light. As speed of light = wavelength * frequency, red...
40. ### How would a white light look in a universe where red light is the brightest?

How do I start "building" a universe in which red light radiation is the highest wavelenght radiation possible? I was wondering, if I lived in a universe in which red light is the "most powerfull" source of radiation, would I be able to detect a, for example, bright white light shining...
41. ### How is white light made up of all the colours in visible light?

In a light bulb, is the filament made up of elements which each produce a colour of visible light to make white?
42. ### Can Pulsing White Light Reveal Its Component Colors?

Is it possible to pulse white light from a source and see colors .
43. ### Uncovering the Mystery: The Science Behind White Light and the Sun's Spectrum

Okay, it may be a dumb question, I am probably missing something obvious... Let's consider the Sun. There is only, say, hydrogen and helium. Both elements emit light of only certain wavelength, so where would the rest of the spectrum come from? Or maybe those wavelengths are restricted only to...
44. ### Interference using white light

Homework Statement What will happen if we use white light at young's double slit experiment? Homework Equations interference The Attempt at a Solution Will we observe several colors on the screen because white light is composed from several light with different wavelengths? Thanks
45. ### Impact of white light source on fringe pattern

Homework Statement Hi A little help will be appreciated (a)Double slit interference fringes are observed using light of wavelength 590nm abd a pair of double slits of spcing o.50mm. The fringes are observed on a screen at a distance of 0.90m from the double slits. Calculate the...
46. ### Colors in white light visible to the naked eye?

Hello, Simple question: Should they be visible to the naked eye? I googled it, but havent found any closely related material :) Im really interested in this, but have no required knowledge to really answer this question nor explain it properly. Best Regards
47. ### White Light Scanning: How Does it Work?

ow does white light scanning work? I know the system is used in industry to measure parts for dimensions like diameter, size. I know there is a white light source. There is a camera mounted at a known angle relative to the white light source. I was told the signal is obtained from the center...
48. ### White Light Scanning: How It Works & Benefits

How does white light scanning work? I know the system is used in industry to measure parts for dimensions like diameter, size. I know there is a white light source. There is a camera mounted at a known angle relative to the white light source. I was told the signal is obtained from the center...
49. ### Does White Light Exist? (And two possible explanations for black lines)

So I'm reading "In Search of Schrödinger's Cat" by John Gribbin, a delightful and concise history of modern physics and I was reading about spectral lines and it said that the dark lines in the solar spectrum can be explained by the fact that there's a cooler cloud of element(s) X around the sun...
50. ### Range of wavelength from white light through a diffraction grating

Homework Statement A narrow beam of collimated white light falls at normal incidence upon a transmission grating with 3150 lines per cm. A spectrum is formed by the grating on a screen 30 cm away. If a 1 cm square hole is cut in the screen its inner edge being 5 cm from the zeroth order...