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.

Filter by
Sorted by
Tagged with
0 votes
0 answers
22 views

Why we have not observed one proton and one neutron nuclear decay? [duplicate]

I'm learning about nuclear decays: Alpha (helium nucleus, +2) Beta (electron) Gamma (photon) Neutron But why helium nucleus? Why not hydrogen nucleus (deuterium)? I mean why two protons and two ...
0 votes
1 answer
41 views

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 ...
0 votes
0 answers
19 views

Calculate total number of fluence on a moving detector

We have a radiation zone emanating from a source located at $(x_0, y_0, z_0)$. We also happen to have the flux due to this source measured in a 3d cylindrical grid surrounding the source with a flux, $...
2 votes
2 answers
31 views

How do physicists know that some of a beta ray/particle's 'missing' energy isn't lost to interference with the electron cloud surrounding the atom?

Enrico Fermi and Wolfgang Pauli ultimately concluded that beta decay resulted in an electron and an electron antineutrino leaving a nucleus... BUT... How does the electron leaving a neutron punch its ...
0 votes
0 answers
24 views

Electric field from an oscillating electric dipole

In the case of two charged spheres connected by a wire and separated by a distance d, when we drive the charges back and forth in the wire (by applying an oscillating electric field), we then have a ...
0 votes
2 answers
54 views

Why is beta minus particle denoted to have -1 proton number?

Why is beta minus particle denoted as having -1 as proton number?
45 votes
16 answers
9k views

Why is radioactive half-life constant?

Say you have just four radioactive atoms with a half-life of one hour. (I am using a small number of atoms to keep it simple and illustrate my confusion more clearly). So that means one hour from now, ...
1 vote
1 answer
13 views

Diffrence between thermionic emission and photoelectric emission

Thermionic emission involves heat energy to excite the electron and remove it. In the photoelectric effect, a beam of light is involved. As per my understanding heat and photons, both are energy. Heat ...
0 votes
1 answer
24 views

Find the maximum possible energy for a beta-particle decay-chain [closed]

So I have this problem where I'm supposed to find the maximum possible energy for a $\beta$-particle in the following decay-chain: The first decay: $$^{90}Sr\rightarrow ^{90}Y + \beta^- + \bar{v}_e$$ ...
3 votes
1 answer
57 views

Cloud chamber shows initial rain effect but no tracks

I am trying to make a cloud chamber but it does not work yet. I do see a rain effect at the beginning which means that the alcohol is condensing and the rain effect slowly disappears as the vapor gets ...
2 votes
2 answers
1k views

Radiation-Glossy Black vs Matte White

Well, studying the chapter Heat I know that a matte black body radiates heat more than a glossy white one but can anyone give me an answer about what happens when its a glossy black body and a dull ...
3 votes
1 answer
592 views

Is diamond a good neutron moderator?

The title mostly says it: Is diamond as a material a good neutron moderator for nuclear fission reactors? Or: Could you build a nuclear fission reactor with diamond as a moderator, instead of graphite....
1 vote
3 answers
994 views

Multipole expansion of the electromagnetic field

In Jackson's Classical Electrodynamics, section 9.7, he develops the multipole expansion of the electromagnetic fields in terms of the vector spherical harmonics and the spherical Bessel and Hankel ...
4 votes
2 answers
2k views

Antimatter bomb

I stumbled upon this wikipedia article on antimatter weaponry. Being greatly appalled by the sad fact that large sums of money are being wasted on this, I could not stop myself from thinking for a ...
1 vote
1 answer
61 views

Radioactive Tracer - calculate fraction that decay before excretion

I was reading about the use of Technetium-99m as a radioactive tracer, how it decays via gamma emission but is also excreted by the body. Assuming the body handles Tc-99 and Tc-99m the same, some will ...
1 vote
1 answer
27 views

Radiation pressure at a oblique surface

I am doing a problem that asks the radiation pressure of a beam of light on a oblique surface. The problem says: A laser beam of intensity I reflects from a flat, totally reflecting surface of area A, ...
0 votes
1 answer
36 views

How does gamma radiation ionise atoms?

I am having trouble understanding how gamma radiation can ionise atoms. I think it is due to a lack of understanding about how photons work. My basic understanding is that gamma radiation doesn't ...
1 vote
1 answer
31 views

What range of light on the electromagnetic spectrum are produced by the de-excitation of electrons?

When an electron moves from an excited state to its ground state, a photon is emitted, which is the source of light. However, I know that the highest energy form of light, gamma rays, are produced ...
0 votes
0 answers
21 views

Intensity of Compton scattering photons

In various sources (1, 2, 3, 4, to name a few) I have seen this graph shown below, that shows how intensity depends on the wavelength of the scattered photon $\lambda'$. Now, I do understand what ...
6 votes
9 answers
3k views

Confusion about Length Contraction (ex in Muon decay)

I am a bit confused about the implications of length contractions; For example, in the muon decay problem, we assume that the distance between the muon and the earth is contracted only in the frame ...
0 votes
1 answer
52 views

How to estimate the power produced by this small U-238 check source?

I got this sealed check source to test my pancake detector (tube model is LND 7317). But I'm wondering if it's worth trying to collect some of the tiny amount of power it's producing as a fun home ...
0 votes
1 answer
39 views

Is Terahertz SAR imaging of Earth possible?

The Terahertz band is at the Wavelength range of 1 mm to 100 μm, which is very good for synthetic aperture radar aka SAR since the shorter the wavelength the better angular resolution you get. ...
3 votes
1 answer
91 views

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 ...
13 votes
6 answers
2k views

Is there any thing other than time that "triggers" a radioactive atom to decay?

Say you have a vial of tritium and monitor their atomic decay with a geiger counter. How does an atom "know" when it's time to decay? It seems odd that all the tritium atoms are identical except with ...
1 vote
1 answer
81 views

Phonons and radiation [closed]

I am trying to understand whether this would impact radiation at all, since the Schrodinger's cat joke and first semester quantum mechanics lay pretty heavily into the idea that radiation is quantum ...
2 votes
2 answers
51 views

Why do electrons come to ground state even after giving absorbing energy?

Imagine you have a hydrogen placed under sunlight, now if we look at 1st shell of hydrogen, it has energy of $-13.6$ev now for 2nd shell we have energy of $-3.4$ev. 1st shell -> $-13.6$ev 2st ...
0 votes
2 answers
40 views

Density problem [closed]

Spacecraft are commonly clad with aluminum to provide shielding from radiation. Adequate shielding requires that the cladding provide 20. g of aluminum per square centimeter. How thick must the ...
3 votes
1 answer
88 views

Spacelike geodesics of FLRW radiation universe

I'm having an interpretation problem with the radial spacelike geodesics in the flat radiation dominated universe. I'm using standard conformal coordinates $\eta \ge 0$ and $\chi \ge 0$ for the ...
0 votes
5 answers
216 views

Radiation and cancer

We were doing a radiation experiment, in my physics class. Obviously, all of the students why crying in fear of getting cancer. The brief explanation given by my teacher, as to how radiation exposure ...
0 votes
0 answers
24 views

Alpha decay of 202-Rn

We were given the following decay scheme of 202-Radon in the 0+ state, with Q-value 6.7737 MeV Spin-parity Energy above ground state (keV) E_a I_a $0_2$+ 816 5836 0.0018 $2+$ 604.94 / / $0_1+$ 0 ...
0 votes
1 answer
26 views

Does the absorption of ionizing radiation increase the absorber temperature?

Let's say a gamma ray shielding material (assume water) has absorbed 1 joule of gamma ray ionizing radiation, does the absorbed 1 joule eventually end up as heat in this material? I ask this question ...
1 vote
0 answers
65 views

Hawking radiation question

A stationary observer near the black hole horizon will detect Hawking radiation proportional to their local acceleration. If we call $\alpha=\frac{GM}{r^{2}}\frac{1}{\sqrt{1-\frac{2GM}{r}}}$ the ...
0 votes
0 answers
17 views

How can I perform particle identification with a proportional counter? I mean, how am I able to discriminate between an alpha particle or beta rad?

As far as I understood for PID you need to know the momentum, the charge and the energy loss by the particle. So if I measure a certain energy loss with a proportional counter how can I know that I ...
21 votes
2 answers
3k views

Why doesn't orbital electron fall into the nucleus of Rb85, but falls into the nucleus of Rb83?

Rb83 is unstable and decays to Kr-83. Mode of decay is electron capture. Rb85 is stable. The nuclei Rb83 and Rb85 have the same charge, but Rb85 is heavier than Rb83. While gravity acts more strongly ...
0 votes
1 answer
32 views

Why $\rm Ag$ 108 decays into $\rm Cd$ 108 most of the time?

In the table of nuclides, it shows that $\rm Ag$ 108 can go through either electron capture or beta- decay (though the branching ratio for electron capture decay is much lower). What determines that? ...
27 votes
2 answers
13k views

Is it safe to keep uranium ore in my house?

I bought 5.6 gr of uranium ore. The measured gamma radiation is 1µSv/h, we didn't have the instruments to measure alpha/beta radiation. EDIT: The gamma radiation was measured at 1cm distance. I also ...
2 votes
4 answers
12k views

Why Rutherford used only gold foil in his famous gold foil experiment?

why didn't Rutherford use an aluminium foil, or a silver foil. Why he used gold foil in his gold foil experiment?
0 votes
2 answers
54 views

How can negative beta-decay energy be negative?

The International Atomic Energy Authority (IAEA)'s Nuclear Data Services list tables of nuclear data, including a table of atomic masses and beta decay energies, data taken from Huang et al., Chin ...
0 votes
0 answers
15 views

Acceleration due to incident radiation on plate

I have tried the following question and getting a wrong answer. Monochromatic light of intensity I falls over a blackened plate of area A, at an angle $\theta$ as shown in the figure. If 70% of light ...
1 vote
3 answers
68 views

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 ...
0 votes
0 answers
35 views

What would be the theoretical energy required to make a "microscopic" temporary black hole that could move an atom?

I stumbled across some videos/news about The Large Hadron Collider and all the panic around the possibility of it creating a black hole. Of course, it is impossible to create a black hole and from all ...
2 votes
1 answer
211 views

Why does water easily absorb THz radiation?

It is stated that water is extremely sensitive to THz radiation, absorbing big amounts of this radiation, this being a reason why skin measurements are safe to do using this range of frequencies (1) (...
4 votes
4 answers
3k views

Wavelength and penetration by EM radiation

I'd like you to clarify the relationship which relates penetration power by EM radiation with its wavelength (or inverse of frequency). Suppose we conduct an experiment, irradiating a body with ...
2 votes
1 answer
317 views

Radiation Density Parameter Today

I would like to insert in my thesis the value of the radiation density parameter today with its appropriate error and I was checking the latest Planck results here. I am a bit confused since I thought ...
1 vote
1 answer
41 views

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 ...
8 votes
5 answers
407 views

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 ...
0 votes
3 answers
64 views

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? ...
0 votes
4 answers
70 views

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 ...
1 vote
0 answers
33 views

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 ...
0 votes
1 answer
24 views

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 ...

1
2 3 4 5
29