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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Electrons in Atom in different energy states

I have a very basic doubt in Bohr's Atomic Model. I just studied that an electron can go to any Energy State with in the atom, by getting relevant energy from photons. If an electron goes to 2nd ...
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Will a radioactive ball conserve its angular velocity?

Consider a uniform spinning sphere in vacuum. In principle it should spin forever, because of angular momentum conservation. However, assume that the sphere is made of radioactive material: since it ...
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Cavity and black body radiation

If one speaks of the fact that one gets blackbody radiation in good approximation by a cavity with hole, does one mean as blackbody this hole, i.e. the place where the radiation exits from the cavity? ...
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What are some household sources of radiation detectable with a geiger counter?

I recently started rock tumbling with my preschool-age kids and bought a cheap geiger counter to check out rocks we find (more from curiosity than concern). Specifically it's a GQ GMC-500Plus model ...
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Why aren't electrons accounted for when calculating the energy of nuclear decay? [duplicate]

In my physics exercises, I had to calculate the energy generated by the decay of an atom of the isotope 40 of K by Beta - decay. It gives us the products: isotope 40 of Calcium and one electron. When ...
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How can beta decay change elementary particles?

From what I read on beta minus decay, when it happens a neutron gets "converted" into a proton, an electron and an electron-antineutrino. I also read that both the neutron and the proton are ...
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Unexpected distingration energy value during alpha decay equation [closed]

I am trying to solve the disintgration value of the below decay equation but the issue I am having is my result seems way to high compared to what is expected (around 5-6 MeV). $$^{213}At \rightarrow ...
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Can point masses following geodesics and orbiting one another emit gravitational radiation?

I am a bit confused about this situation: according to general relativity, when two masses orbit one another, they emit graviational waves, which carry away certain energy. For example, check out ...
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Do unstable nuclei affect each other for decaying?

I am thinking about beta decay. If we graph decayed nuclei count over time, we don't see a linear line. Rather, it would be a curved line. I imagine myself as an unstable nucleus. If I don't care ...
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Does thorium-232 emit X-rays?

The question is derived from an experiment... "Red" tungsten TIG welding electrodes consists 2% of thorium-232. They are slightly radioactive... I have such electrodes, so I checked their ...
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How was the black body intensity vs wavelength (or frequency) radiation curve historically produced?

I have read that Wilhelm Wien gave his formula to match the radiation curve of a black body as shown in the picture; which works well in high frequency region. Another formula by Rayleigh-Jeans is ...
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Black body side of the Moon

A few closely related questions regrading the Moon thermodynamics: The Moon is clearly not a black body, as it reflects a great deal of radiation incident on it. Still, it does absorb some radiation ...
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Has there been experimental confirmation of electron capture being a neutrino source?

Detecting nuetrinos is not easy of course but it seems that there are several interesting ways of playing with neutrinos using radioactive sources that can only decay by electron capture. For example, ...
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How does air cool as it nears the poles?

I understand air is heated by the equator causing it to rise towards the poles. But why does air cool and sink after nearing the poles. Shouldn't the air still possess heat, after being heated by the ...
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How long does it take, and how much heat, to raise the temperature of air in a box?

I am seeking to crudely model a house with a window as a perfectly insulated box with a hole (which only allows radiative heat). My question is to find how the temperature of air in the box changes ...
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If plutonium-238 (Pu-238) absorbs a neutron, does it become Pu-239?

I am asking this simple question because I am always hearing about how thorium reactors are less perilous to the world because, unlike uranium reactors, they produce some Pu-238, which is not suitable ...
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How is Alpha Radiation possible?

Alpha radiation would seem to occur when a pair of protons and neutrons are magically plucked from the amorphous (i.e. having no particular structure) nucleus of a heavier atom. Some of the problems ...
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How do electrons escape nuclear reactors to cause Cherenkov radiation?

From what I understand, nuclear reactor cores are shielded, so that gamma rays don't get too far too often. But since electrons are expected to penetrate less material, then how are underwater nuclear ...
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What would happen if an atomic bomb exploded on a nuclear power plant?

Would the effect be different than if the nuclear power plant were bombeb with traditional explosives? Would the atomic bomb neutralise any potential radioactive effect of the obliteration of the ...
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How exactly Radiocarbon dating Works?

So how exactly does Carbon Dating work ? $^{14}$C is produced from $^{14}$N in the atmosphere. Since there is considerable amount of Nitrogen in the atmosphere,we can have quantifiable amount of $^{14}...
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Working out radiation rates

Suppose the radiation dose of a CO-$57$ source was measured to be $63$ mR/hour $5$cm away from the source. Is there any way to measure the radiation at the source? ($0$cm from the source). I thought ...
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How dangerous is 1R/hour, and how to calculate whole body effective dose?

If I understood correctly, 1 R will deposit 0.96 rad in a 1 cm3 of soft tissue. If an adult male has a volume of 87,000 cm3, does it mean their body will absorb 83520 rad in one hour? I feel like I ...
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Can the lifetimes of excited states be calculated (specifically for $4^3D_{5/2}$)?

How do I find the lifetime of the excited state $4^3D_{5/2}$ for $Rb^{87}$? I know the lifetime of $5^2P_{3/2}$ (which is 26.24 ns), and according to this link, the spontaneous emission rate is ...
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Can gamma rays pass through Geiger-Muller counter?

Im trying to build a custom Geiger-Muller counter with an argon tube ( i’m still choosing to use wether argon 36 or 40 ) . The fact is that the counter will be made of multiple tubes which are all on ...
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Ionizing radiation energy in joules

The energy level at which radiation can be labelled as ionizing is about $10.00-33.85$ eV. This (the $33.85$ eV) is equivalent to $5.423368\cdot 10^{-18}$ Joules. In terms of joules this is a very low ...
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Radiation Pressure derivation

Radiation pressures mathematical expression according to Wikipedia is, $\frac{1}{\mu_0 c}\vec{E} × \vec{B}$ "Radiation pressure is the mechanical pressure(force/area) exerted upon any surface due ...
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Ratio of specific entropy after a particle decay

I am working through the following problem (not homework, but revision), and would appreciate some feedback on my answers to parts (b) and (c). For part (b), I used Friedmann's first equation ...
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Energy density per solid angle?

How does this make sense? Energy density is usually a function of position (maybe time,frequency also) How could it also be a function of $\Omega$ , i.e the solid angle ? For context, $ u(\Omega)$ ...
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Why is there an upper mass limit of $300$ GeV of the Higgs boson for $W/Z$ associated production and t$\bar{\mathrm{t}}$H associated production modes?

I am currently trying to understand this graph for the cross-section versus Higgs mass: As you can see from the above graph, there is an abrupt cut-off at $M_H=300$ GeV where I have put a green box ...
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Microwave Oven Radiation

I read that microwave ovens are allowed by FDA to emit max 5mW/cm2 electromagnetic radiation at about 5 cm from the surface: https://www.fda.gov/radiation-emitting-products/resources-you-radiation-...
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Can the variation of count rate over distance for a disk radioactive source be treated as an electric field of a disk charge problem

So I did an experiment in which the count rate of a disk source of Sr-90 is measured using a plane detector, varied from ~0.7cm to 100cm, multiplying the count rate by the distances squared (i.e. $\...
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Why radial radiation profiles of axisymmetric electric arc cross section is Gaussian?

I've recently found from experiment data that, the radial intensity profiles of an axisymmetric electric arc cross section is pretty close to Gaussian Distribution (R-square>0.99). fitting image ...
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Magnet spindown in a vacuum

How long will it take for a strong neodymium magnet with a mass of 1kg to spindown in free space (vacuum) due to the radiation energy loss and hence the loss of angular momentum?
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How many Tesla can stop 1 Sievert?

The SI unit of Magnetic field is Tesla. The magnetic field of Earth blocks all the radiation coming from space which is measured in Sievert. I'm designing a solenoid that can counter the radiation ...
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Why do we take the average temparature of the container?

I have been working on a problem of blackbody radiations and was asked to find the time taken to reach a particular temperature, I have used Stefan's law which states that the emissive power $E$ of a ...
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Cosmic String Radiation

Given the high mass density of a cosmic string, wouldn't passing charged particles falling into them emit light at least in the radio spectrum? Thus shouldn't we be able to see filaments near sources ...
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Pair production and recombination with a more energetic beta particle

Can gamma particles with sufficient energy for pair production gain energy by recombining their positron with a more energetic beta particle than the one they produced? If yes, is this something that ...
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3 votes
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Is radioactive decay deterministic? [duplicate]

Suppose you know at time $t$ that there is some atomic nucleus that radioactively decays. If you were to magically roll back the universe to the exact same state and let it continue as per usual ...
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$Q$ values for 3 types of beta decays

For the three types of beta decay: \begin{align} _z^AP&\rightarrow {}_{z+1}^AD + e^-+\bar{\nu} & Q_{\beta^-} &= (M_P-M_D)c^2 \\ _z^AP&\rightarrow {}_{z-1}^AD + e^++{\nu} & Q_{\beta^...
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Why is $\beta^+$ decay possible for $\text{Cu}$-64?

When Cu-64 undergoes positron emission, we have $$_{29}^{64}\text{Cu}_{35}\rightarrow_{28}^{64}\text{Ni}_{36}^-+\beta^++\nu + Q_{\beta^+}.$$ The $Q$ value could be calculated as 0.653 MeV. I wonder ...
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Can we define x-rays as as decelerated electrons?

HI I'm a student and i was reading up about x-ray production. I realized that after the electrons hit the metal plate( usually tungsten) x-radiation is produced. Is it that the metal ironizes and the ...
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8 votes
3 answers
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How can I determine if an element undergoes electron or positron emission?

I'm not sure how I can determine whether an element has $\beta^-$ or $\beta^+$ emission, or no $\beta$ emission at all. I'm told that positron decay happens when there are too many protons and not ...
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Why is the isotope Lithium 6 stable against alpha decay?

According to the table the binding energy of Helium 4 is 7.073915MeV/Nucleon while the binding of Lithium 6 is 5.606291MeV/Nucleon. So why is the lithium 6 isotope not an alpha particle emitter? I ...
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Nuclear Physics - Meaning of Terms in Beta Decay Hamiltonian

I am new to nuclear and particle physics, but am familiar with the concept of a Hamiltonian and nonrelativistic quantum physics. In this paper by Yang and Lee on parity conservation in weak ...
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Does accelerated charged particles violate the conservation of energy?

While trying to understand the Wheeler–Feynman absorber theory, I read that the motivation of the theory was to explain why accelerated charged particles doesn't violate the conservation of energy by ...
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Is all transformation of quarks and neutron happen for $\beta^+$ decay?

In the video, the person had said "when proton comes in" they form neutron, positron and neutrino. I was thinking what he meant by "comes in". Was he talking about any kind of ...
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Beta decay breaks conservation of momentum? [closed]

Just considering the decay of a free neutron, the change in rest mass, .732-ish MeV, leaves as kinetic energy of the electron and neutrino. Doesnt this break conservation of momentum since the neutron ...
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2 votes
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Are quantum events such as decay, emission, absorption and tunneling truly instantaneous or is there some small time period? [duplicate]

Are quantum events such as decay, emission, absorption and tunneling truly instantaneous or is there some small time period? Assuming there is an underlying cause for a quantum event it seems to me ...
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3 votes
1 answer
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Can you electrostatically charge materials with X-rays?

I am wondering if by making use of the photoelectric effect someone using for example X-rays radiation could electrostatically charge positively a dielectric like glass [1] and make it therefore ...
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How much x-rays and heat is released by a high speed electron when collided with a surface?

We know that when an electron hit a target (surface) at very high velocity (or with high acceleration),it produces x-rays and heat. So my question is how strong the x-rays and heat will be,if velocity ...
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