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.
1
vote
0answers
30 views
When (Exactly) Does Bremsstrahlung Radiation Occur?
Regarding the Bremsstrahlung Radiation emitted when a charged particle curves inside a uniform magnetic field; Is there a way of calculating the angle through which the charged particle will precess ...
1
vote
1answer
88 views
When should angles be expressed in degrees vs. radians?
I am trying to calculate the albedo of a given latitude by following the methods of Brutsaert (1982), I have copied the formula below:
3.6 Shortwave and long-wave radiative fluxes
Albedo ...
0
votes
0answers
39 views
Find mass of Plutonium in alpha decay [closed]
I did:
$$\Delta mc^2 = (m_{Pu}+m_{U}+m_{He})c^2$$
$$\frac{5.24 \times 10^6 eV}{(3 \times 10^8)^2} = m_{Pu} + 235.043924 + 4.002603$$
$$m_{Pu} = 239.0465$$
But answer is 239.052157, slightly ...
0
votes
2answers
89 views
How can we detect a black hole? [duplicate]
If black holes are phenomena of very high density (gravitational singularities) which don't emit radiation how can we detect them so far away from us where so much other radiation can hide the black ...
1
vote
1answer
23 views
What type of Radiation hits Europa
I was recently reading the Wikipedia Page for Europa as I am interested in terra-formation. In one of the sentences, it says that:
The radiation level at the surface of Europa is equivalent to a ...
1
vote
2answers
64 views
Alpha particle and helium nucleus
The symbol for the alpha particle is α or $α^{2+}$, it can be written as $He^{2+}$.
What I want to know is that, are they same? I mean alpha particle and helium nucleus are same or any subtle ...
4
votes
1answer
92 views
What is the difference between Radiation and Electromagnetic Radiation
Are the two equivalent or is Electromagnetic Radiation a subset of Radiation. I am further confused by the fact that electromagnetic radiation includes both ionizing and non ionizing types of ...
0
votes
1answer
44 views
Computing $\Delta m$ in $\beta^-$ decay
$\require{mhchem}$What is the energy $Q$ released when $\ce{^131_53I}$ decays and $\ce{^131_54 Xe}$ is formed? The atomic mass of $\ce{I}$ is $130.906118~u$ and the atomic mass of $\ce{Xe}$ is ...
8
votes
4answers
174 views
Why are alpha particles such a prominent form of radiation and not other types of nucleon arrangement?
It is said in many textbooks that alpha decay involves emitting alpha particles, which are very stable. Indeed, the binding energy (~28.3 MeV) is higher than for $Z$-neighboring stable isotopes. But ...
1
vote
0answers
24 views
Effective amplitude in Neutrinoless double beta decay
Can someone give me the value of the effective amplitude($A$) of $\bar{\nu_\mu}\rightarrow\nu_\mu$ oscillation of Neutrinoless double beta decay? The expression is like this:
...
11
votes
4answers
140 views
$\beta^+$ decay
We've been discussing radioactive decay at school, and I grasped everything except for $\beta +$ decay. When I googled radioactive decay, I immediately found out they dumbed down radioactive decay for ...
3
votes
1answer
281 views
Kinetic energy of alpha-particle in $^{212}$Po decay
Admittedly, Nuclear Physics is not my strength. I'm writing a simulation to model alpha-decay. So far, I have looked up the values of the kinetic energy of the alpha particles that are emitted in a ...
3
votes
1answer
40 views
Is a beta decay possible with out the emission of an electron in the process?
Is a beta decay possible with out the emission of an electron in the process ?
Beta decay involves the formation of a proton and an electron from a neutron.
0
votes
0answers
23 views
Probability in Radiation Physics for electrons [closed]
The total linear attenuation coefficient for 10-keV electrons in water is 77.6 μm^-1, partitioned as follows:
Elastic scattering 38.2 μm^-1
Ionization 37.4
...
0
votes
0answers
50 views
Temperature of an Object in Space [closed]
Rotating cylinder in space
Hi all
I've been having problems trying to calculate the temperature of an object in space, and was hoping I could get some help. Say we have a cylinder in space rotating ...
2
votes
4answers
203 views
Modeling incoming solar radiation
I want to write a model for estimating incoming solar radiation for a specific latitude on earth but I am struggling to find an appropriate source which shows the required equations for doing so. ...
0
votes
0answers
95 views
Calculating the Heat Losses of Convection and Radiation [closed]
A water pipe for central heating with length $L=10m$ and diameter $25 mm$ is running over a cold attic with $T_{air} = 278 K$. The radiation temperature of the surroundings is usually lower than the ...
0
votes
2answers
85 views
Can there be energy with no force or energy with no power?
I think that both force (number of newtons) and power (p=ui(?)) implies that there is energy so we can't have force without energy and we can't have power without energy(?)
But can there be energy ...
2
votes
1answer
129 views
Does an object's color change its rate of cooling?
The motivation for this question comes directly from this thread. The proposition is that the color of something changes how fast it cools (note: specifically the rate of cooling, not taking into ...
0
votes
1answer
44 views
effects of sunlight through a glass window?
Both my father and my grandfather where drivers, and over time ended up with a wrinklier left hand compared to the right hand, due to sunlight exposure over 40+ years while holding the steering wheel ...
2
votes
2answers
60 views
Is it possible to record the 'blue air" effect when a core goes critical?
I've been studying about radiation, and I saw something called the Demon Core. Apparently, it was a core that was under experimentation by the government in Los Alamos to see the exact point at which ...
1
vote
1answer
34 views
Nuclear transition notation
I have a question which asks me to determine what x is for the following nuclear transition
$$^{29}Si(\alpha, n)X$$
But I don't have any idea what this notation implies.
Another example:
...
1
vote
1answer
49 views
What was the first ionization radiation?
While trying to make somewhat of a timeline of the history of ionizatig radiation, i am wondering about the following questions:
The first photoelectrical effect was found 1839 by Alexandre ...
-1
votes
1answer
100 views
Determining energy of gamma-rays after alpha-decay of Am-241
So it turns into Np, and electrons just falling into 'free new' levels and emmiting, right?
Give me a link where to read, please, if it's very easy to answer.
2
votes
1answer
60 views
The equal opposite reaction of radiation pressure
If the photons of a laser would produce a radiation pressure upon whatever it shown upon wouldn't it be accurate to say that the laser would be propelled in the opposite direction of its beam?
0
votes
0answers
67 views
Beta decay for Ar-38, K-38, Cl-38
I want to prove that $^{38}Ar$ is stable with respect to $\beta$ decay, that $^{38}Cl$ decays by $\beta^-$ and that $^{38}K$ decays by $\beta^+$.
I know from Googling that this is true, and I also ...
4
votes
1answer
54 views
$\alpha$ decay to more than one nuclear state
I do not understand how $\alpha$ decay can be a probabilistic process such that there are multiple products from the decay. For example:
$^{241}\mathrm{Cm}$ decays to the excited states of ...
0
votes
0answers
49 views
Radiation question [closed]
I am having some trouble with the following question
Sam is seeping into a room from the basement at a rate of
$$\frac{1}{6} \times 10^6 \frac{\mathrm{pCi}}{\mathrm{hr}}$$
(pCi=picocuries). The ...
4
votes
1answer
130 views
Radiation exposure to a child who was briefly in the presence of an adult who had received a 18FDG PET scan
I am a physician who thought she was good at math, but apparently am not as I cannot figure out this mathematical/physics question. (My background is obviously NOT nuclear medicine!) A family friend ...
2
votes
2answers
119 views
Would a laser with four possible energy levels be better than three?
I'm wondering about achieving population inversion for a laser. I learned that without an active medium, it's not possible to create a laser with only two energy levels, but it would be possible with ...
1
vote
2answers
82 views
Quantum yield and spontaneous decay
I'm trying to figure out how many atoms are decaying spontaneously in a span of 2 seconds. Let's say that the quantum yield is 0.45, and that the lifetime "τ" (tau) is 10 microseconds.
Then I found ...
2
votes
1answer
78 views
Question on Radiance equation
The radiance equation is
$$
L = \frac{d}{dA} \frac{2(\phi)}{dW cos(\theta)} (watt/srm^2)
$$
where $\phi$ is the flux.
I am thinking, should not be the cosine term on the numerator instead of the ...
1
vote
1answer
103 views
Specific electron energy gap values $E_{i+1}-E_i$ vs. photons with arbitrary energy $\hbar \omega$
The energy levels of electrons in an atom are quantized $E_i$. A photon of a specific momentum $\vec p$ and energy $$\omega=(E_{i+1}-E_i)/\hbar$$ hits an atom and gets absorbed. Okay now say the ...
1
vote
2answers
191 views
A hot object exposed to low temperature in a vacuum doesn't lose heat?
I heard somewhere that if the human body were exposed to outer space where the temperature is extremely low, the human won't actually feel cold because in a vacuum, the heat energy doesn't have ...
0
votes
2answers
216 views
Is it possible to speed up radioactive decay rates? [duplicate]
Possible Duplicate:
Do some half-lives change over time?
Would it be possible to considerably speed up the decay rate of an isotope?
Considerably meaning more then a 1 or 2% increase in ...
2
votes
0answers
24 views
Surface UV exposure with cooler star
If the sun's surface was ~ 4000K (and earth closer to compensate), the UV component of the radiation would be less. However, UV makes ozone via photolysis of oxygen. Also, the stratosphere would ...
0
votes
1answer
67 views
What is the relation between surface area and radiation, if any?
Basically I wonder what happens to emitted radiation by douubling a light e.g. twice the surface area of the sun will emit how much more radiation? 4 times more? Is there a formula?
0
votes
1answer
56 views
Does it happen at high energies (heavier leptons decay)?
A lepton is an elementary particle. The best known of all leptons is the electron which governs nearly all of chemistry as it is found in atoms and is directly tied to all chemical properties.
The ...
0
votes
0answers
37 views
Non reflecting boundaries in waveguides
Can someone please explain the Sommerfeld radiation condition and what is the alternative non-reflecting boundary conditions for waveguides of general geometries?
3
votes
4answers
475 views
How do electrons jump orbitals?
My question isn't how they receive the energy to jump, but why. When someone views an element's emission spectrum, we see a line spectrum which proves that they don't exist outside of their orbitals ...
3
votes
2answers
288 views
How to interpret Stefan-Boltzmann's law?
The Stefan-Boltzmann equation states $e=\sigma T^4$, but how do we interpret this?
Is this completely wrong: A body of size $s^2$ generates the radiation/temperature $T^4$ for a given size and a ...
6
votes
4answers
583 views
Can you speed up radioactive decay of plutonium?
We all know the issue of deep geological repositories for fuel rods. Is there a way to speed up the rod's decay to render them harmless in less than 10 years?
1
vote
0answers
32 views
Effect of Background Radiation on a Transmitted Signal
I'm coding a basic simulation of using error correcting codes to transmit data from a satellite back to earth. I'm not sure what to set the "noise level" to. Let's say a satellite orbiting Mars ...
1
vote
0answers
28 views
Half-Life Question [duplicate]
Possible Duplicate:
How do we know that some radioactive materials have a half life of millions or even billions of years?
I understand how to calculate decay, but it seems to me that the ...
1
vote
2answers
111 views
How to detect radiation on the metal (coin)?
I've got metal coin : http://www.worldpeacecoin.org/
Ruble/dollar, a coin of disarmament with certificate. But, I am very spleeny person, I fear of it's radiance level and I don't know if I can trust ...
0
votes
0answers
76 views
The Deflecting System in a Hot Cathode Ray Tube
In an HCR-Tube, the deflecting system used to deviate the electron beam is made of positively charged plates. How is this justified? If, due to some malfunction, the electron beam deflects from its ...
2
votes
1answer
49 views
Range of electromagnetic waves
I was reading this article. There is a statement "It is a well-known fact that the telecom towers mounted with antennas in the lower frequency bands can cover far greater areas than those using the ...
4
votes
1answer
1k views
What common materials can effectively block infrared radiation?
I have a plastic container and want to make sure that infrared radiation (specifically, in the 750-850 nanometer range) cannot pass through it. Would wrapping it in aluminum foil do the trick? If not, ...
0
votes
1answer
108 views
How to choose a $\alpha$, $\beta$, $\gamma$ measurement detector?
There are many different detectors for different radiation,such as NaI,HpGe,CsI for $\gamma$ detection,and ionization chamber,proportional counter,Geiger counter for $\alpha$, $\beta$ detection,but ...
0
votes
0answers
57 views
Which of the following radiation measurement devices is suitable to measure the radiation level in a Data Center? [closed]
Which of the following radiation measurement devices is suitable to measure the radiation level in a Data Centre?
Geiger Mueller (GM) Detectors with Pancake Probes
Alpha Radiation Survey Meter
...
