Light Definition and 1000 Threads

I've wondered what would happen to a particle if it could break through the 186,000 miles/second speed barrier and go faster than light. Would it go say 186,001 miles/second or would it go infinitely fast. I know Einsteins Special Relativity prohibits this but I have just wondered. Now if this...

Welders use a logarithmic scale to identify protective eyewear. The shade number n, is given by the equation n = 1 − 7logT/3 , where T is the fraction of visible light that glass transmits. a. What shade number should a welder use that only transmits ⅛ of the light entering the glass? b Viewing...

The intensity, I of light in lumens, passing through the glass of a pair of sunglasses is given by the equation I(x) = I0 (0.8)^x , where x is the thickness of the glass in millimetres and I0 is the intensity of light entering the glasses. How thick should the glass be so that it will block 25%...

1. I'm fine with this one, I simply calculated L = L0/γ = 5/1.2 5= 4m. 2. This is the one I'm having problems with. My approach was to say that both observers would measure the light beam to have velocity of ‘c’. Therefore, if 4m is the distance between the mirrors as observed in the frame of...

This is an example from a textbook. They show the following: ∫nds = ∫r-2*ds = ∫r-2*√((dr)2+r2*(dθ)2) How do you obtain the expression for ds?

I watched a documentary where it's said that light coming from the core of the sun takes thousend of years to reach the surface of the sun. Why is this so?

What sensor to would i use to measure the difference in wave length periods. I want to make a rendered image of somthing that field of view that is being obstructed.

I noticed that if I hold two small rounded quartz stones together in front of my eye, with light shining on them from the other direction, I see what looks like a very distinct, black, noisy waveform between them. Does anyone know the detsals about wy this happens?

I am sure this will become a 'face-palm' moment, but can anyone point me in the direction of what electromagnetic energy wavelengths on either side of the visible spectrum, that is detectable on earth, ie what is not filtered by our atmosphere? I am specifically trying to find information on the...

0.8m -> 800mm λ = (0.4mm*1.1mm)/800mm = 0,00055mm is it right? I am past that 3 months ago, forgot how to solve.

Can anybody explain why the bright and dark fringes exist during the the interference phenomenon from two coherent sources.. I wanted to know why that specific pattern occurs

Hello, I've been studying electromagnetics, electromagnetic radiation, and bit of quantum electrodynamics for about 12 months, but I'm stumped on an issue.. This is what I understand so far: Charge consists of countless "vacuum fluctuations" (i.e., virtual particles). Accelerated charges...

I'd like to know if anybody can tell me either; How large a wheel would have to be for the outer edge to travel faster than the speed of light if powered by a motor that's around now. We'll say the wheel is in outer space to eliminate drag and such

An electromagnetic wave has a phase speed and a group speed. Or velocities, for that matter. In a medium, the phase speed of a wave is generally determined by the medium's permeability μ and permittivity ε. What are the general parameters that determine the group speed of a wave in a medium?

Summary: Will an external surface reflect light into a more focused beam without using a traditional lens? Hey guys. Just trying to focus the light coming from a 1watt LED light source. It's native beam angle is 130 degrees. I'm hoping to focus it to around 30 degrees. We are creating an...

Hello, I'm wondering if you can inform me about that kind of light which be projected on a glass and it helps us to see it's reflection only for the viewer and not for anyone the other side . all proposals and methods are welcome. even if it is necessary for the light to pass on a chemical...

Ok so I'm having trouble understanding how to calculate this If an object is moving so fast that it would take... "Hours for light to catch up to it" .. how fast would it have to be moving? Let's say it would take 2 hours for light to catch up to it. What kind of speed are we looking at...

Summary: how can a train traveling at light speed, travel at two different speeds being the same train, depending upon whether you are on the train platform or in the train You say good bye to your friend at the train station. You get into train that will travel at just under light speed...

Summary: Dark matter, the elusive mass that makes up most of the universe, doesn’t interact with light. Is this because it travels faster than light itself? I have been working on the maths and the theory for several months now in order to discover the nature of dark matter. By rearranging and...

I was watching this video by Don Lincoln, one of the senior researchers at FermiLab, on the the reason light slows down in transparent media (air, water, glass, plastic, etc...). He explains that the photons excite the electrons in the medium, which in turn add to the wave (or at least that's...

I am studying the fact that two events that are simultaneous in a frame aren't (in general) simultaneous in another. The lamp is equidistant from the two ends. When the light is switched on an observer on the train sees how both light rays hit the back and the front of the train...

I have obtained seeds of a rare rhododendron species. These seeds are contaminated (experimentally determined). While I have tried several common methods, none decontaminated the seeds. Lately, I have read that so many joules of UV light at approximately 254nm will prevent replication and...

I am wondering if an object can fall into a black hole at faster that the speed of light. I have heard that the expansion of the universe can make distant galaxies appear to recede from one another at velocities faster than the speed of light.

 Intuitively, this makes sense to me. I am...

Before I modeled it, I thought the current would move in a figure 8 due to the battery on the right still loading the current. Then I thought of how the battery on the left would counteract that current. I am still not sure what is going on here. Is it kind of like a short circuit where the...

If my car can travel the speed of light will the head lights still work?

what would cause the phase difference ?

I hope someone here can explain this curious light effect! Some background: I have a table with a laptop on it, and a chair sitting at this table that has a mesh back on it that has a pattern of ~2mm holes cut into black material in a regular pattern. I happened to notice one day that I could...

Since electrical charges causes a sparkle or a crackle which is light and sound. Also light and sound are forms of energy does that mean that electrical discharge releases energy and if yes then the release of energy have an effect on charge

I have a question I have been wondering about lately ,somewhat abstract . Hopefully my description will be adequate . Here it is … The Earth revolves around the sun because of the suns gravitational pull and Earth's inertia . It takes about 8 minutes for sunlight to reach the Earth . What would...

1. How did one came to the constant 299 792 458 m/s? 2. Why this particular number? Why not 521 334 992? 3. Why can't we travel faster than the speed of light?

I want to understand the concept of polarization of light. I would like someone to clarify how I am thinking about it: If light is a transverse wave and it is basically an electric field(E) and magnetic field(B) each oscillating in different directions (axes) which are perpendicular to each...

Can an everyday magnet disturb a ray of light. I have seen many answers online saying no, and some saying yes, but only if the magnetic field is large enough.

I think I can write the density matrix as $$\rho = \frac{1}{2} ( |R \rangle \langle R | + |L \rangle \langle L | ).$$ The state of a linear polarized light in the direction ##\textbf{a}## can be write as $$|\theta \rangle = \frac{1}{\sqrt{2}} ( e^{-i \theta} |R\rangle + e^{i \theta} |L\rangle...

I know that the answer is NO because now there is an extra substance (the fluorescent powder) that is affecting the emission. However, i don't know how fluorescent powder works in this case. I tried to search it up and only found that Fluorescent powder will 'fluoresce' when it absorbs UV...

Quantum entanglement does not imply that you can send information faster than the speed of light since you cannot manipulate what your sending. You don't know what you have until you have measured it. But you do know that you have the corresponding photon at the other location in space no matter...

Been trying to figure this problem out for a couple hours now, if i use 400 nm into the equation it comes out to 800: 400=sin(30). If i do 700 nm it comes out to 1400: 700=sin(30). I feel like i’m doing somethingwrong with the problem but i can’t figure out what.

Hi everyone, in the attached file I tried to find the transmitted and the reflected coefficients. I ran into trouble applying the boundary conditions to the linear components of the electric field. Check the outlined boxes and see if they make sense. Thanks

In a vacuum the speed of light is a constant. What if its not in a vacuum? Okay, as always I'm confused. I'm very interested in physics but am a layman. Alright, so we know that time is relative to one's distance from a mass, so that as we go further from the Earth, let's say, time moves...

My understanding of light has been that it travels in a perfectly straight line unless reflected or refracted by some object. Treating light like physical objects (like pool balls bouncing off the sides of a table) has been useful for situations where geometry can be used to find things like...

Hi all, I am hoping someone could clear up a concept that doesn't make sense to me. I am thinking in terms of a blackbody diagram, which is "Intensity" on the y-axis and wavelength on the x axis. I understand that when you heat something to a higher temperature, the curves shift to shorter...

Here is the question (Qu 9): Here is what I have attempted: assumed that the accelerations are equal, found a value for the acceleration, thus worked out the time taken for A to reach the bottom. then assumed that the tension becomes 0 once A hits the floor, and then worked out B's new...

It is said that interference occurs when a peak (of the light wave) meets a trough and the wave cancels to zero, giving a dark band on the screen. However, if light waves are bands or "shells" of high densities of photons interspersed with bands of zero photons, then how can this be? When a peak...

The second postulate says the speed of light is constant c independent of all inertial observers. Does it mean the speed of the wave front relative to the observer , that is, the relative speed between the wave front and the observer?

Curious if the ongoing studies of black holes at the centers of galaxies, like the Event Horizon Telescope, might provide some clues about the nature of dark matter. Tried googling this, but all I get is articles debating, mostly to the negative, the hypothesis that dark matter might be...

I'm a physics student, and working on a class project that requires coming up with a method to control the exit angle (diffraction angle) of a monochromatic light source. For example, taking a laser (monochromatic, coherent light source), spreading the beam, and directing the light at a piece...

Hi everyone, this is sort of a soft question which I need to ask to make sure my understanding is correct, it relates to a little project I'm doing on measurement resolution. The first question is to clear up a general concept, the second is based on the first and is the actual question...

I need to calculate irradiance in a system shown on the image. There is an infrared LED on the left and a diffuser in front of it. I need to calculate irradiance at a certain distance after the diffuser. I think I first have to calculate irradiance at the diffuser. Then multiply it by the...

In a double slit experiment, is diffraction caused by interference or interference is caused by diffraction?

Thanks for being here, this is my first post. Imagine on a dark night a very powerful beam of light was aimed at the sun from earth and switched on, at 23:00. I am observing from side on, in space, at a distance far enough away to get a good view of the beam as it travels out into space on its...