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43 votes
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How many X-rays does a light bulb emit?

The formula you want is called Planck's Law. Copying Wikipedia: The spectral radiance of a body, $B_{\nu}$, describes the amount of energy it gives off as radiation of different frequencies. It ...
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35 votes
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How would an X-ray scanner identify a mirror?

The thing that makes a mirror a mirror is a that it has a high reflectivity (and is very smooth of course, but that doesn't enter into this issue), but all optical properties including reflectivity ...
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27 votes
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Why do X-ray telescopes have to be in space?

X-ray (and gamma rays) are quite penetrating. They can pass through solid matter with much less attenuation than visible light as an example. But that doesn't mean that the attenuation is zero. Put ...
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26 votes

How would an X-ray scanner identify a mirror?

dmckee points out that an ordinary mirror doesn't reflect X-rays, but if you could find an X-ray mirror and put it in your case it would just appear black. When you look at yourself in the mirror you'...
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23 votes
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What's the difference between Hard X-rays and Gamma-rays?

It can be a little confusing because there are two conventions. The modern convention is to distinguish x-rays from gamma rays by how they are produced. X-rays are produced by electron energy ...
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20 votes

Why do X-rays go through things?

You have to distinguish, which interactions take place, when electromagnetic radiation passes through a solid and interacts with it. There is a nice plot on Wikipedia, showing the dielectric response ...
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18 votes

How would an X-ray scanner identify a mirror?

As others have noted, an ordinary mirror will not reflect x-rays. X-ray mirrors do exist, but will also probably not do what you want here. It's very difficult to manipulate the optical trajectory of ...
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  • 281
17 votes

Why don't X-rays penetrate the bone?

Bones absorb more xrays than soft tissue because of the Calcium in the bones (and the high density helps too, but the same densities of, say, Carbon or Silicon, wouldn't absorb as many x-rays). The ...
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15 votes

Do free-electron lasers actually lase?

FELs produce a coherent, monochromatic, intense light beam that can be collimated with an iris (basically a hole in a large lead block). An optical cavity can be arranged by putting two mirrors ...
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13 votes
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Do x-rays and gamma rays also contain photons like visible light does?

Yes, X-ray, UV, and even radio waves are made of photons. The difference is the Energy (or equivalently, the wavelength). See the picture of the Electromagnetic spectrum . The different nomination ...
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13 votes

Why do X-rays go through things?

Light is composed out of a large ensemble of photons, and photons are quantum mechanical elementary particles. Matter is composed out of atoms and molecules , which have small dimensions and are in ...
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12 votes

How many X-rays does a light bulb emit?

The wavelengths of light emitted can be calculated using planks law and the temperature of the object. For your average 100W incandescent light bulb, the filament is 2823 kelvin according to google. ...
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12 votes
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Do free-electron lasers actually lase?

You are missing a crucial aspect of the dynamics of a Free Electron Laser: microbunching. This comes from the fact that although electrons at different energies share basically the same velocity $c$, ...
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10 votes

Why we don't use gamma rays, x-rays or ultraviolet to transmit data?

For data transmission through optical fibers, what you have to worry about is finding the correct material for transmitting the light over long distances. Consider the following diagram for the ...
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  • 2,909
10 votes

Computers That Can Compute in Femtoseconds

There is a lot of confusion in this question. Let me try to clear up some of it. First, the LCLS II is not yet running. The LCLS II is expected to begin operation in 2022. However, SLAC is doing ...
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9 votes

How would an X-ray mirror work?

Unfortunately X-ray and gamma mirrors are impossible to build the way you think - mainly because there is much less interaction with the matter comparing to UV - it will go through all materials ...
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  • 2,842
9 votes

Why can x-rays pass and not radio waves?

A Faraday cage need not be a continuous conductor — you can make a reasonable Faraday cage out of chicken wire. The rule of thumb is that if the gaps in the conductor are small compared to the ...
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8 votes
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Medical X-Ray - why no diffraction?

Since the lattice spacing is about eight angstroms, the issue isn't any sort of unusual lattice spacing. Instead, the issue is that bones are thick. [Another answer points out that the crystals are ...
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8 votes

X-ray image of the Earth

This experiment has sort-of been done. As far as I know, no X-ray satellite has captured an image of the Earth eclipsing the Sun, but HINODE observed an eclipse of the Sun by the Moon at X-ray ...
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8 votes

Why do X-ray telescopes have to be in space?

To extend very slightly upon BowlofRed's answer: X-ray photons interact with electrons. More electrons in an atom means more interactions, and more interactions means less penetration. In general ...
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8 votes

Why do X-ray telescopes have to be in space?

Is water transparent? It seems so in a glass, but a kilometer of water is nearly opaque. The deep ocean is dark. Air at atmospheric pressure is similarly opaque to x-rays on a kilometer scale. It's ...
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  • 5,526
7 votes

How can we detect X-rays?

There are many ways to detect X-rays. I will list just a few that are (or have been) used in medical imaging. Essentially there are several strategies, but it always involves stopping the radiation ...
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7 votes
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How large should an optically large fusion reactor be?

I think that this is an interesting question and I will try to give a very rough answer (warning: it might include some approximations). Instead of calculating the optical thickness of the D-T plasma,...
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  • 1,889
6 votes

Do free-electron lasers actually lase?

If you use "population inversion" as an essential part of the definition of what a laser is, then you're right it's not a laser. But that doesn't deny that the properties of light can be just light ...
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6 votes
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Units used in X-ray energy spectrums

I think the way to read your "hash" ("#") is as "number." What you've plotted here is a differential spectrum: the number of x-ray events observed in each energy window from $E_i$ to $E_i + \Delta E$....
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6 votes
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Can X-rays emitted due to bremsstrahlung radiation have frequency matching with other EM waves like visible ones?

The continuous X-ray spectrum comes from Bremsstrahlung radiation, which is the radiation emitted whenever an electric charge is accelerated or decelerated. In this case electrons striking the metal ...
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5 votes

X-ray pulse more powerful than national grid?

I can't find details on the pulse energy and duration of the LCLS, but it's entirely plausible the power could be greater than the national grid of a large country. The power is energy divided by time,...
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5 votes

X-ray image of the Earth

X-rays work by being absorbed in denser material, producing the shadow that is the traditional X-ray image. Medical X-rays are designed to top out looking at calcium-40 ($Z$=20). On an object the size ...
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5 votes
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Are there solid-state devices that can produce x-rays?

The problem is what mechanism can you use to produce X-Rays with solids... atomic or molecular, band transition, whatever you use in solids do not enter the X-Ray regime when it comes to produce high ...
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