Light Definition and 1000 Threads

I was watching this video ... And basically the video show how adding in middle angle polarized filters it makes more light to pass. Then comments about quantics and blah blah blah. Why cientifics thinks lot weird and how was discard the following line of a more natural thinking: My...

Homework Statement Approximately 4% of the intensity of light is reflected at a glass-air boundary. Classically one expects roughly 8% of light to be reflected from a thin glass plate (4% at the front and back boundary). Outline briefly what quantum theory predicts for a single photon instead of...

Hello, I have a simple question regarding current flow through a common part of a circuit. I encountered this as I am reading "Code: The Hidden Langauge of Computer Hardware and Software" by Charles Petzold. The images I've attached display what I'm talking about. I'd like to know if there's a...

1. What is the advantage of using class 2 laser light? I would really appreciate if reference source is also given!Homework Equations Not needed.[/B]The Attempt at a Solution Well, I thought that using monochromatic light would made it easier to measure the distance between fringes. And also...

Using Newton's 2nd law F=ma, If you provide a constant force of 1mil Newtons then an object will accelerate at 100m/s. Using V = U + AT I can say that (speed of light) 299,792,458 = 0 + 100T thus T = 2997924.58 seconds or I can achieve speed of light in 35 days or so. Why is this not...

visible light contains a range of frequencies i.e not of single frequency, then how visible light is used as a carrier in Visible light communication. Further more is it possible to modulate light (in tera HZ frequency range). what modulation scheme is possible and how it is implemented in VLC...

Just wondering how a photon reacts when it is affected by gravity of an object in space like a star. Does the gravity actually bend the light/photons? Say you have a series of photons in a perfect line, all travelling, well, at the speed of light toward a massive object(x). The photons in the...

I don't know what's the appropriate title for my question but here it is: What's the reference we consider to measure the speed with respect to when we say that as the speed of a moving object approaches the speed of light the time becomes slower in the frame of this moving object.

Any one please tell,all experiment attempt to find speed of light

Is it possible to modulate light as it is to modulate sound.?That is, taking "white" light and changing its color without using a filter or another object like a prism?

Homework Statement Given that the relative magnetic permeability and relative electric permeability of water are respectively, ##\mu_{rel}=1## and ##\epsilon=1.769## calculate the following 6 parameters. 1. Index of refraction of water ## n ## 2. speed of electromagnetic waves in water ## c...

Please see my attachment of a recent observation of light traveling through a medium. There is no source, just my observation The packets of light appear to be visible, distinct , moving at different speeds, and display the various colours for each wavelength. Is this normal / possible in a...

Hi All I read somewhere that at close to C the light emitting from a regular light globe ie diffuse light in all directions, will form a cone. what is the thinking behind this and does anyone have a link where I can read about it ?

Homework Statement How does this picture represent a unpolarised light?Homework EquationsThe Attempt at a Solution [/B] I thought light waves were perpendicular to the direction of propogation so if it has diagonal components then isn't that not perpendicular to the wave direction If it is...

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...

I build the following spectroscope: However, I'm not sure how it works. I thought that the light entered the slit, diffracted from the CD (because the tracks in them are comparable to the wavelength of visible light) and then we observe the different components in the...

Ambient for lack of a better term... I'm reading "Beyond The Cosmic Landscape". Perhaps out of date, but a very understandable explanation of QED. Am I right to deduce that the air which surrounds us is jam-packed with electrons emitting photons? Thanks...

Light is Reflected from the surface of the object or pass through it(interior) and then the light is reflected ? Sorry for my "noob" question i am a 3D designer just looking for some more knowledge Thanks in advance

How fast would you have to go to reach a star 240 light years away in an 85-year human lifetime? Here, I know that I'm supposed to find $v$, but I'm having a hard time setting up my equation(s) in order to reach the final answer. :(

Hi all! In Young's double slit experiment, there are two things I cannot explain. Any help is appreciated! The first one is why the bright fringes get dimmer as you get further from the central/brightest spot. My theory, after looking in the two books I have, is that each single slit decreases...

Hey guys So lately, I've been interested in circuits. I am good at maths, but my physics isn't as good (hence why i signed up to ask questions). So I have a question. Imagine you have a simple circuit, like below: Simple circuit, 1 bulb and X amount of batteries. So my question is, how many...

A quick question about this type of apparatus. The apparatus itself is composed of 2 concentric hollow cylinders. The cylinder at center is cooled below -50C. The atmosphere around the outer cylinder is at room temperature. This creates a temperature gradient in the space between the cylinders...

Hello guys , I will make this brief.Does anyone know why Semi Conductors are more sensitive to light than other materials? For example Semi Conductors are used in Photovoltaic cells.

Hello Here is the shadow of the edge of a screen. This picture is in one of Mr Feynman's books. (Http://www.feynmanlectures.caltech.edu/I_30.html) Of course, there is light interference in the edge of the shadow. It's normal. It's diffraction. Mr Feynman explains how to geometrically build this...

I read that atoms transition from electronically excited to vibrationally excited. But how?

I've been told that when a photon of light is created it instantly achieves the speed of light without having to 'speed up". How is this possible?

I have unpolarized light passing through a polarizator assuming the angle 0°. The polarized light then passes through two quarter-wave plates, the first one with the angle of 45° (maximum intensity) and the other one. Then it passes through a last polarizator having an orientation perpendicular...

I was reading a book called Catching the Light; a book on the history and other interesting things about light. There is a discussion in the book about refraction such as one might see when looking at a stone at the bottom of a pond when viewed at an angle. I've always just thought of the...

Special relativity requires any substance to be compressible. Indeed, if an item were made of a perfectly rigid substance, then move one end of it, and the other end must move at the same moment - the movement must be transmitted instantly, faster than light. Thus, the special relativity sets...

Hello, If the speed of light is the maximum speed limit in our universe, how was the big bang event possible because surely the expansion would have been constrained by the speed of light?

So an object unaffected by any gravity free floating in space has zero mass. Now could this object reach light speed. Or am I confused?

Hello everyone ! At High School I have to make a little robot which is steerable with light. It has 2 photoresistors, if a photoresistor received light it switches on a motor. That allows us to go leftward or rightward. But, I have a problem. I don't manage to link every components between us...

If I had a white light bulb and covered it with the right colour of film (red-ish) will the resulting wavelength be about 700nm?

A question about the light-waves and the double-slit experiment: Light can be polarized: If you turn a polarization sheet in a polarized beam of light, you can see that polarized light has an angle. So the light-wave is transverse (right?) But how does a transverse wave ‘bend’ as it goes...

Homework Statement a) explain why a pattern of bright and dark fringes is visible on a screen when a light is shone through a double slit. b) Use this data to determine the wavelength of light being used to create the interference pattern. Do this three different ways. -The angle to the eighth...

This matter would be able to do everything that light does.

This question has been bothering me for decades: Imagine a point source in space that emits one photon per second. Would the photon expand in a globe in all directions until it strikes an object or would the photon shoot off in a random direction? Suppose you have one target ten meters away...

Hi, I'm doing a very simple problem, but I don't understand the diagram provided (see image below). What is m here? I know that m is the order with respect to the central bright fringe, but there isn't a central bright fringe (assuming those circles are the bright fringes)? Homework...

Hello - I'm posting this here because of a discussion I got into on another forum following the recent death of Stephen Hawking. I should stress that I am by no stretch of the imagination a physicist (though I did do modules on special relativity and quantum mechanics as part of my maths degree...

Need to overlay beams by having one replacing the other where they intersect rather than have the beams be superimposed. this is what I want: https://i.imgur.com/F6HIYBl.png this is what I do not want: https://i.imgur.com/ylhMeEa.png This kind of beam combining can be either achieved by the...

When the sun's rays break through a cloud there appears a radiating pattern but if one drew a line through these rays they would meet much closer than the distance to the sun. How come?

A rocket is in constant velocity. The velocity of the rocket is 150Mm/s (or 0.5 of the speed light, or 150 million meters per second) relative to us (we as observer). We observe two lights, one moving in parallell with the rocket, another is moving in the opposite direction. Below I have made...

Does the speed of light change in different substances, or does it seem to change because it gets absorbed and emitted by all the particles?

In order for a conventional telescopic riflescope to function, it must invert the image two times. As a result, the light-rays traveling through the tube must meet at two focal points. With my limited knowledge of optics, i assume that parallell light going in through the objective will meet...

I am trying to piece together how the parabolic mirror manages to reflect the "red dot" from the focal point to the eye without distortion. I compare this with a conventional car headlight, which operates almost exactly the same way, except it has a non-transparent backing. Why does the ret dot...

Homework Statement Homework Equations n1/n2 = (sinθ2)/(sinθ1) = v2/v1 The Attempt at a Solution Moving from a lower refractive index to a higher refractive index. ( Lower density to higher density means faster speed to slower speed) The answer is answer B, I don't understand why.

Respected physicists and members (I am not a physicist) I have a little doubt that i want to clarify. If I am sitting in a stationary train, having a ball in my hand, the ball will remain stationary relative to my hand and plateform. Now if the train starts moving, again the ball is stationary...

Hi All, Due to the differences in their conductivities, but considering that both the metallic and the glass plane surfaces produce mirror images of objects, is there any difference in the explanation of the mechanism of reflection of light in these materials?

Is it possible that the speed of light exists because we cannot move faster than our particles? I.e. the speed of electrons that create the electromagnetic force that hold matter together.

I know that Maxwell discovered that a disturbance in the electromagnetic field propagates at the speed of light - which Occam's razor would say that light being such a wave would explain it - but not definitively that that is true (e.g., gravity waves, or at least at that time in history, some...