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.

learn more… | top users | synonyms (2)

1
vote
2answers
41 views

Radiation from home heaters

My understanding of radiation is energy being emitted from a source. So much radiation would come out of a home gas or oil heater to become dangerous. I'm assuming infrared radiation.
4
votes
0answers
69 views

The logarithmic decay of WIFI

I have been told that Wi-Fi, LTE etc signal strength fall of as $$\propto \frac1{\log(r)}$$ where $r$ is the distance. I am wondering why this is. I better explain what I mean with this question. ...
1
vote
1answer
39 views

Kalb-Ramond action and topological string radiation

Let's have simple scalar $\Phi$ action involves spontaneously symmetry breaking in a form $$ \tag 1 S = \int d^{4}x\left( |\partial_{\mu}\psi|^{2} + \psi^{2}|\partial_{\mu}\theta |^{2} - ...
1
vote
1answer
46 views

What's the idea behind Wu's experiment?

Madame Wu discovered the parity violation in beta-decays. To do so, she took some Co-60 nuclei, which decay via beta-decay in Ni-60 with emission of electron, antineutrino and 2 gamma rays. She ...
0
votes
1answer
28 views

Why did scientists use a zinc-sulfide coated screen to detect the alpha, beta, and gamma radiation?

How does a zinc-sulfide coated screen work, and how does it manage to detect high-frequency radiation, electrons, and helium? Could it be possible that a delta ray managed to somehow slip past ...
0
votes
0answers
41 views

How to derive the Gamow factor in the simplest way?

I want to know how to derive the Gamow factor (how to solve the integral and which approximation I have to do) without the centrifugal correction. $$V(r) = V_N(r)+V_c(r). $$ The Gamow factor is ...
3
votes
1answer
73 views

Why is the energy spectrum of alpha decay discrete?

Are the other peaks with lower energy caused by the possibility that daughter nuclei have to be in excited states?as show in this link (count versus energy)
0
votes
4answers
105 views

Has cosmic microwave background kept a constant frequency?

Has the frequency of CMBR changed at all since the beginning of the universe? Has it always had a microwave frequency or has the frequency increased/decreased over time or is the change due to factors ...
16
votes
6answers
4k views

Can UV light make us invisible?

For an object to create different EM waves, it needs to increase the temperature, so what if we or some material could be so hot, that it would emit ultraviolet light, and thanks to that be invisible ...
0
votes
0answers
27 views

Annual and daily cycle in solar radiation

I would like to reproduce the following diagram: where the figure on the left hand side shows the daily cycle of solar radiation and the rhs shows the annual cycle of solar radiation for different ...
4
votes
2answers
248 views

Why is the excited state of 116 Indium more stable than ground state?

Why is the excited state of 116 Indium more stable than ground state? Both undergo beta decay, but the ground state has a half-life of 14 seconds, while the excited state has a half-life of 54 ...
1
vote
1answer
46 views

Quantum mechanics prediction for Bremsstrahlung?

Does quantum mechanics predict the Bremsstrahlung Phenomena? I know it is predicted by classical mechanics through Maxwell's equations, but does QM predict this phenomena and how so?
2
votes
1answer
36 views

Black Body Radiation ELI5

If a black object and a shiny object were left in vacuum and bombarded with thermal radiation would the shiny object eventually reach the same temperature as the black object? The reason I ask is I ...
0
votes
0answers
9 views

Clarification on isotropic sources and fields

For an isotropic radiation field the net flux is zero, something I find quoted in a lot of notes and text on radiation. We often think of isolated stars as isotropic sources, but their net flux is ...
2
votes
2answers
88 views

Deflection Effects on a Spinning Solar Sail

Suppose I have a solar-sail-powered starship flying directly away from a star. The sail is flat and perpendicular to the direction of travel. Now, in order to make the trajectory more stable (we ...
0
votes
0answers
17 views

Is there a way to cause scintillation of air particles using an artificial source?

Is there an artificial source that can cause scintillation of air (nitrogen, oxygen, etc. )? What does it emit and what is the range?
0
votes
1answer
32 views

ionising atom(s) with gamma rays

if a gamma ray hits an electron and transfers energy, does it hit that electron (ionising the atom), transfer all its energy and stop or does it pass through multiple electrons, transferring a portion ...
2
votes
2answers
69 views

What Happens to electrons after Alpha Decay and Nuclear Fission?

Where do the electrons go? In alpha decay do 2 electrons follow the alpha particle and make stable Helium or does the larger daughter nucleus become an anion? Also what do the electrons do in the ...
13
votes
1answer
300 views

How hot would tritium water be?

I realize this is kind of a silly question, but if you have tritium water, with the tritium half life of 12.5 years, I expect it would be quite hot. (note, this is not a homework question, I'm just ...
2
votes
2answers
83 views

Can an element decay into an infinite loop?

I've been working on a problem and have been wondering is there any isotope of any element that beta decays under certain conditions but then under differing conditions the daughter nucleus electron ...
2
votes
1answer
103 views

Highest temperature possible to achieve using magnifying glass and sunlight [duplicate]

Temperature of the surface of the sun is about 5750K. Can you heat an object to more than 6000K using magnifying glass and sunlight? According to second law heat cannot be transferred from colder to ...
-3
votes
3answers
76 views

If radiation didn't exist, would everything live longer? [closed]

I recently noticed that dying of old age is similar to a death by radiation - hair loss, weakened immune system etc. and I was wondering - Does background radiation limit our lifespan, or that of any ...
4
votes
1answer
35 views

Temperature effects on lead against radiation

I would like to know if bringing lead to near absolute zero temperatures would have any affects on how resistive it is against gamma radiation. It takes 40 centimeters of lead to reduce gamma ...
3
votes
2answers
54 views

What minimum energy is required to create tracks in a cloud chamber?

What is the minimum ionizing radiation required for that? I am currently living in Fukushima prefecture and I was wondering if let`s say a flower from my yard that emits 1 pSv will create visible ...
3
votes
3answers
103 views

How does radiation degrade mechanical parts and electronic devices?

I'm running out of places to look (lots of Googling, SE, [articles and books are too specific and never give a good overview]), and yet I am still unsure about how exactly radiation can degrade ...
2
votes
0answers
22 views

How to calculate material depth at which penetrating radiation direction becomes randomized?

Consider a very light particle impinging on a material composed of atoms which are effectively infinitely heavy (e.g., because they are bound together and stiff). If the scattering with nuclei is ...
1
vote
0answers
21 views

Klein-Nishina for estimating X-ray cross section

I'm looking at interaction probability for X-rays with water and DNA, and recently have starting reading up on the Klein-Nishina identities for differential cross section. When integrated over all ...
1
vote
1answer
23 views

Understanding view-/formfactor for radiation with a specific example

There is radiation coming from a point source (black body). How much of the total emitted energy (from the point source) hits a spherical surface given by $\phi = 0 - \pi $ and $\theta = 0 - \pi/2 $? ...
2
votes
2answers
67 views

Alternatives to the neutrino in the beta spectrum?

It is well known that the neutrino appeared to explain the power distribution in the beta decay spectrum. (see PSE) What other explanations candidates were available? It is stated that the ...
0
votes
0answers
25 views

Polarisation states in 1d?

I am working through a derivation of the spectral energy density in a 1d cavity. The derivation says that the number of modes (per unit volume) in a frequency interval $dv$ is given by: $$g(\nu)d\nu ...
0
votes
1answer
39 views

Can someone explain the radioactive decay of that would happen over time to a 1 cubic decimeter block of plutonium? [closed]

I just saw an article talking about naturally occurring plutonium on Earth and it said that some [or many or some other purposefully ambiguous statement] people think this element could [another good ...
2
votes
3answers
428 views

How do particles “know” when to decay?

So, as I understand it, in a substance that is made of radioactive elements, the half-life tells us how long until the half of those atoms decay into their next atom [is there a name for that: the ...
1
vote
1answer
25 views

Measured temperature (thermometre set to emissivity of 1) of smooth surface too high or to low?

We want to measure the temperature of a smooth flat surface with a thermometre based on absorption of thermal rays. The emissivity setting of the thermometre is set to 1 (same as a black surface), ...
0
votes
3answers
120 views

Is heat from a stovetop, transfered through convection, radiation or conduction?

It doesn't appear to be convection, as there are no moving objects (or are there); probably not radiation (?), so it is conduction? I really don't know much about heat transfer and thermodynamics, ...
9
votes
3answers
798 views

How do we know that the cesium-beam frequency used in atomic clocks is always the same?

Atomic clocks use cesium-beam frequency to determine the length of a second. This has shown that the period of orbit of the earth is decreasing. But what experiment showed that cesium-beam's period ...
17
votes
2answers
3k views

Why doesn't the evening/morning sun feel much hotter on your face?

I understand that places on the Earth's surface get hotter in summer, and in the middle of the day rather than morning or evening, because the surface of the Earth is presented 'face-on' to the Sun at ...
2
votes
2answers
184 views

By what maximum amount can we concentrate sunlight?

This refers to a previous question re: Solar Cell Systems and as part of the answer the statement: If we concentrated sunlight to [the] maximum amount 42600× was given. My questions are: By what ...
2
votes
1answer
194 views

Increasing the efficiency of solar cell systems

As far as I know, there are currently two main approaches to utilising solar radiation for maximum energy conversion to electricity. These are either direct conversion to electricity, using ...
0
votes
1answer
103 views

What is the difference between zero background radiation and field background radiation in Nuclear Physics measurements?

Can someone please explain the difference between these two terms (Zero Background Radiation and Field Background Radiation) used in radiometric prospecting measurements?
1
vote
1answer
32 views

Carbon 14 disintegration

When $\beta^-$ disintegration happens to a Carbon 14 atom, a neutron "turns into" a proton, and an electron is emitted. Therefore the result of the disintegration is a Nitrogen atom plus an electron ...
1
vote
1answer
59 views

What is the energy threshhold to produce Cherenkov radiation?

I am in a nuclear course right now and am getting some misleading information from different sources. I am trying to figure out what the minimum total energy is that a proton must have in order to ...
1
vote
2answers
50 views

How does “contamination” through (radioactive) radiation work?

Physically, what does it mean when people or objects are contaminated with radiation? Is it because they actually carrying heavy metal particles?
1
vote
1answer
57 views

Surfaces that reflect UV rays

I've been trying to research what surfaces reflect UV rays for the past day but it's been difficult coming up with definitive answers. So far what I've found is that surfaces that reflect visible ...
1
vote
1answer
28 views

Does the W boson in beta decay affect the gravity generated by the system?

During beta decay we now know a heavy W boson gets involved temporarily. Would this potentially impact the gravitational field generated by the system as a whole? It doesn't seem like it should. Just ...
0
votes
1answer
173 views

Relationship between temperature and wavelength?

I am investigating the relationship between wavelength and temperature. As seen the figure below of Planks law What is the relationship between the lambda(max) and Temperature? or in simpler ...
0
votes
0answers
39 views

beta minus decay: expression for maximum electron energy

I'm having some trouble finding an expression for the maximum electron energy in beta minus decay. In the frame where the neutron is initially at rest, conservation of momentum reads: ...
0
votes
1answer
42 views

X-ray background radiation

I'm running an experiment in gamma-ray imaging (although the main emission from the decay of Am-241 is ~60keV, so much more in the range of x-rays). I'm curious as to the sort of sources that would ...
0
votes
1answer
37 views

Background gamma radiation

There are plenty of lists of sources of general background radiation, but can anyone reduce that list to the major contributing sources purely for background gamma radiation (specifically low energy, ...
1
vote
1answer
39 views

What process happens in an IT nuclear decay?

I've been researching medical isotopes and alot of them decay by an IT path. Does anyone know what IT stands for? And what physical process is happening? Example: ...
2
votes
2answers
120 views

Why the CMB has not been dispersed so far?

Imagine you have a box of black body radiation. What happens if you open the box for a long time? It becomes dispersed and no radiation remains in the box. Now, apply this example to the Cosmic ...