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Questions tagged [radiation]

Radiation is a process in which energetic particles or energetic waves travel through a medium or space. The particles or waves radiate (i.e., travel outward in all directions) from a source.

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How does particles move in waves? radiation?

I'm reading about particles for a project and had a question. I read that particles don't move forward in a wave, the simply oscillate up and down, and that gives it the wave look. But if they don't ...
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Atmospheric Optical Thickness from flux

Is it possible to calculate or estimate the atmospheric optical thickness given a measured flux? And if so, how?
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How do I get energy distribution of radiation (Planck's Law) in terms of frequency?

I have $$u(\lambda) d\lambda = \frac{8\pi hc\lambda^{-5}}{e^{hc/\lambda kT} - 1}d\lambda$$ I want this in terms of frequency. I can start with $\lambda =c/f$ but I will end up with $u(c/f)$ rather ...
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Does 1/square apply to Energy and or Radiation? [closed]

When an electron returns to its ground state, it does so by the system releasing a photon of equal energy. Does energy experience 1/square as it propagates thur space-time or is that radiation, which ...
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Would plasma that is as electron dense as lead be a better shield than lead against gamma radiation?

Imagine you somehow managed to maintain a body of plasma which had the same electron density as an identical volume of lead or other heavy metal. (Suppose you ionized lead.) Would it be a better gamma ...
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Will a black body placed somewhere around the Sun obtain (eventually) the same temperature as the Sun?

Suppose we look (above the Earth's atmosphere) at the wavelength ($=\frac c f)$ spectrum emitted by the Sun: This shows that the Sun is approximately a black body with a temperature of about $5525(K)....
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Can't see any traces of particles in my Wilson chamber without radioactive material

I am doing an essay about particle physics and I need some help. I am comparing the results in a Wilsonchamber with and without a radioactive material present. I were able to see a lot of traces from ...
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Determination of Dead time of a Geiger Muller counter using the two source method

While determining the dead time of a GM counter using the two source method, why do we ensure that only two sources are placed in the counter at all times i.e. while determining the counts when both ...
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Energy dispersive x-ray spectroscopy of H and He

I have read (e.g. here) that you cannot see hydrogen in Energy Dispersive X-Ray (EDX) spectroscopy spectra because it doesn't have a K-shell. To my mind, even if the element is participating in ...
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why do we use energy density in black body radiation instead of only energy? [closed]

why did we use energy density in the derivation of planks law and also how can we count the number of waves inside a blackbody generated by in internal reflection of waves?
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Forming a Neutron Star: inverse $\beta^-$ decay or electron capture?

There are three different kinds of beta decays: $\beta^-$: n $\rightarrow$ p + e$^-$ + $\overline{\nu}_{e^-}$ $\beta^+$: p $\rightarrow$ n + e$^+$ + $\nu_{e}$ electron capture: p + e$^-$ $\rightarrow$...
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How would a fast-moving atom interact with a body? [closed]

I found this question on Quora: https://www.quora.com/Can-you-theoretically-shoot-an-atom-fast-enough-to-kill-its-target I think the Quora answer is good but incomplete, and it got me wondering what ...
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Is it Possible to Explain a Black-hole by Assuming a Matter-to-radiation Transformation Rather Than The Formation of an 'Infinite' Singularity?

**Is it possible that at the final nanosecond in the formation of a black-hole, particles in the interior of a developing Schwarzschild envelope are colliding at speeds approaching that of light; but ...
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1 Picocuries per liter is how many millirems per year? [duplicate]

How can you calculate how many millirems of radioactive particles occur per year? The measurements don't seem to match up with radon testing information. 333 millirems in a year not accounting for ...
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Satellite radiance measurements in spectral regions

Q: A satellite measures longwave radiation emerging from a planet with uniform surface temperature T1 and uniform atmospheric temperature T2. What values of radiance does the satellite measure in the ...
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Intuition for why matter dominated expansion is faster than radiation domination?

In a matter dominated universe $a_{\rm mat.}(t)\sim t^{2/3}$, while in a radiation dominated universe, $a(t)_{\rm rad.}\sim t^{1/2}$. Therefore, a matter dominated universe is expanding more quickly, ...
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How are solar sails maneuvered by sunlight? Are they pushed or pulled?

On 20 May, 2010, Japan launched IKAROS probe with primary propulsion by a solar sail. If the radiation pressure, that helps the sail to move, comes from the sun, then shouldn't it be pushed away from ...
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Is it possible for antimatter to be created from a nucleus of regular matter decaying?

I have a limited understanding of nuclear reactions. I know of the decay in which a positron is emitted from a nucleus and a proton is converted back into a neutron. There is also another type of ...
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What is the rotation profile for radiative zone of Sun - Instability and convection?

I am exercising on Stellar Physics topics and in particular the questions below: 1) First of all on the rotation profile for the radiative zone: I know that unlike the convective zone, where the ...
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1answer
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Do materials approach black body behavior as temperature increases

I have emittance curves of a material (that cannot be shared) that show an increase in emittance values over a wide wavelength range. As the temperature increases, the value for emittance increases, ...
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What is the incident power of the sun for different parts of the U.S over time?

I have seen number as low as $200\ \text{W}/\text{m}^2$ to $1000 \text{W}/\text{m}^2$. I'm in California and looking for information on how much power my solar panels will pick up. I have $4100\ \...
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When you cook food in a microwave oven, why does't the plate get cooked? [closed]

When you cook food in a microwave oven, why doesn't the plate get cooked?
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How is the Solid in Oven centre Hottest [closed]

When a solid (any material) is placed in an oven and heated, the theory of radiation works I guess. How it the centre of the solid the hottest and not the surface of the Solid which actually receives ...
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Synchrotron Radiation for Electrons, Protons and Ions

I understand the principle of synchrotron radiation in saying that , when a charged particle gyrates around some magnetic field line it emits energy in the form of photons. However I can't ...
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Nuclear reaction – What is the asterisk an indication of?

I've been observing the two-step decay of iodine-131 and can't quite determine what the asterisk above Xenon-131 indicates. I'm currently unsure as to what precisely the superscript asterisk on Xenon ...
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Experimental evidences satisfying charged particle emits radiation in gravitational field

Is there any experimental evidence exist that a charged particle at rest in gravitational field emit radiation and charged particle in free fall don't emit radiation ( According to equivalence ...
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Relativistic motion of particle

Given $\beta=v/c$ and $\gamma=1/\sqrt(1-\beta^2)$ how can I show that $d/dt (\gamma\vec{\beta}) = (\vec{\beta}/\beta^2)d/dt(\gamma) + \vec{v}$, where $\vec{v}$ is a vector perpendicular to $\vec{\beta}...
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Inferring Properties of Stars from Masses and Radii

I have two questions related to inferring properties of stars from their masses and radii. What properties of a star's spectrum could we deduce? In particular, do all stars emit like black bodies? ...
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What is the measured decay rate of antineutrons? / What is the measured mean lifetime of antineutrons?

Please do not post any "answers" dealing with predicted/theoretical estimates. The question specifically asks for measured / experimental evidence.
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Symptoms of lethal neutrino radiation in a hypothetical scenario

Core collapse supernovae release the majority of their energy in the form of neutrinos. According to an XKCD What If, the neutrino radiation alone from a supernova at a distance of just 2 AU would be ...
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Why is Neon not used as a coolant for gas cooled nuclear reactors?

What is the reason that Neon is not considered as good coolant for gas cooled reactors? I haven't found any research nor experiment with Neon in this field. As I checked out Neon has small neutron ...
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Why don't we use positrons from beta plus radiation as a source of anti-electrons for energy?

Why can't we use the positrons (let off by beta plus radiation) as a source of anti-matter, such that we can collide it with an electron for 100% efficient mass to energy conversion?
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How to transform the irradiance image on the screen in the double-slit experiment back to electric field in order to perform Fourier Transform?

Say I perform the double slit experiment while meeting the requirements of the far-field. I get some interference image on the screen (where R is great, as mentioned). This image is correlated with ...
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Proportionality of rate of decay with the amount of nuclei present in the substance

Why is the rate of decay of a substance directly proportional to the amount of nuclei present in the substance? I don't know much about this topic, my teacher introduced us to this concept in class ...
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1answer
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Intro QM representation of Abraham-Lorentz Force

What does the Schrodinger equation look like if you add some term for the Abraham-Lorentz force? I get a self reference term I'm not sure how to handle. I realize this is probably addressed by QED, ...
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Synchrotron emissivity change of variables

I have an expression for an emissivity $j_\nu$ $$j_\nu =a_0 \left(\frac{p}{mc}\right)^2 B^2\; \delta\mathopen{}\left(\nu -a_1 \left(\frac{p}{mc}\right)^2B\right)$$ where $a_0$ and $a_1$ are ...
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Chemotherapy radiation physics in Grey's Anatomy

In the Grey's Anatomy episode "Everyday Angel" airing Thursday 25th, 2018, a patient with growths on each scapula is found to have cancer in these growths. Dr. Jackson Avery is upset that this boy ...
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What is “Radiation damping stronger than inertia.”

I'm reading a paper on creating gamma rays in a lab and I've come across a phrase I simply don't understand; "Radiation Damping Stronger Than Inertia". As I understand it radiation damping is just ...
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Interpreting a nuclear decay scheme

From my understanding, this is a decay scheme that shows the percentage of each energy level at which the disintegrated mother nucleus has reached after the disintegration has occurred. But what do ...
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43 views

How does decay rate depend on energy difference?

From Fermi's golden rule, one knows that transition rate is $$\Gamma_{i \to f} = \frac{2\pi}{\hbar} \left \lvert \langle f | H' | i \rangle \right \rvert^2 \rho \, .$$ However, can we make the ...
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Is there a link between nuclear radiation and sound? [closed]

I'd like to understand if it's possible to relate/imagine a link or relationship between nuclear radiation and sound. A simple description would be appreciated since I don't have a deep understanding ...
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1answer
35 views

In HPGe detector how electron-hole pair remembers energy information of incident gamma?

In the HPGe detector, any gamma energy (> e-h pair production E) shall excite the electron of the valence band and send it to the conduction band. Due to reverse bias, the conduction band e shall be ...
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1answer
42 views

Do Electromagnetic waves exert equal force on positive and negative charges?

Waves in the Electromagnetic fields propagate with the speed of light and have perpendicular E- and B-components. These components should exert a Lorentz force on a charged particle that exists in the ...
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1answer
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Nuclear Instability and Q value in Alpha decay

Alpha decay: $(Z,A) \rightarrow (Z-2,A-4)+ ^4_2He $ According to the book: "Nuclear and particle physics" by Williams, $Q_\alpha$ is the measure of available energy to permit an alpha decay. It is ...
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How much do radiation-resistant suits cost?

Let's say you wanted a top-of-the-line, impenetrable suit to withstand high levels of radiation. How much does one of these suits cost?
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How to obtain the luminosity of a blackbody disk? [closed]

How do I get the luminosity of blackbody disk (negligible thickness) with temperature $T$ and radius $r$? Also how can one obtain the flux density if the object is at a distance $d$ and an ...
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1answer
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hearing Cosmic Microwave Background Radiation

It is often stated that the scientists who discovered CMBR in the mid-1960s "heard" the radiation. Did they actually "hear" it (as in sound)? If so, what was it they "heard"?
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What is the difference between reflection and emission?

What is the difference between a body that simply reflects the light that falls upon it and a body that absorbs and emits it (like a black body in thermal equilibrium)? How can one experimentally ...
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1answer
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Probability of Photoelectric Interactions

I have am currently reading Radiation Detection and Measurement, by Gleen F.Knoll, and in chapter 2 page 49, he talks about the probability of the photoelectric interaction as: $$\tau \approx C \frac{...
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Does a fusor emit dangerous radiation?

I noticed some online videos where people have built these things in their house or garage. Is it dangerous to do so? The high voltage appears to be a potential hazard, but what about radiation -- ...