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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Geiger-Nuttall law alternative form
I've seen the two forms of Geiger-Nuttall law. which is the
$$log\;\omega = aE^{1/2} + b\hspace{5em}:(1)$$ and $$log\;\omega=a'logR_{\alpha}+b'\hspace{4em}:(2)$$
From the range-energy relation, we ...
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Why does a heated body emit a continuous spectrum of waves, while a burning body emits one color?
Why does a heated body emit a continuous spectrum of waves (as I understand it, that's why they burn red/white/blue), and a burning body is one color?
as I understood it, for example, the green flame ...
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Demonstration of constant radiance for Lambertian Surfaces
I'm approaching to radiometry and I'm struggling with one of the properties of Lambertian surfaces.
We know that the radiance is the radiant flux emitted, reflected, transmitted or received by a ...
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Radiation power emmited by a material with two different temperatures [closed]
Let's consider a cylindrical sample of a solid material surrounded by air. From $0 \leq r \leq r_1$ the temperature of the material is $T_1$ and from $r_1 < r \leq R$, $T=T_0$ which is also the ...
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Gravitational wave flux in Effective One-Body (EOB) models
I'm working for my M2 internship on gravitational waves in effective one-body approach, and I'm struggling in understanding how they compute the non-conservative flux from GW radiations. Most of the ...
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Average kinetic energy of a non-relativistic electron in beta decay
I am trying to show that (a bird told me), in a beta decay, the average kinetic energy carried off by a non-relativistic electron is $E_0 / 3$. I have derived that, for the states, a distribution
$$dN ...
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How to measure light intensity in a room?
Does anyone know how I would go about measuring the light intensity in a room? I'm not interested in knowing the lux reading, I would like to measure the $W/m^2$ due to thermal radiation in my ...
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Radiation due to charge particles
We know that accelerated charged particles emits em waves/energy.When we apply voltage across a conductor the electric field applies force on the electrons then why don't the electrons in the ...
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What force expels the negative charged particle in carbon 14?
What force expels the negative charged particle from carbon 14 as radiation ? Is it electromagnetic force, strong force or weak force ??
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Why are absorbing bodies hotter over time than reflecting bodies?
I recently learnt about energy transfer by EM Waves and came across the formula for momentum transfer, i.e.
Δp = U/c → perfect absorption
Δp = 2U/c → perfect reflection
then why do absorbing bodies ...
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Why is $^{176}\rm{Lu}$ so stable with respect to $\beta^-$ decay?
The nuclide $^{176}\rm{Lu}$ (spin $7^-$) can decay to the $6^+$ state of $^{176}\rm{Hf}$, with a $Q$ value of $593.33\,\rm{keV}$. The change in spin $J$ and parity $π$ is only $\Delta J^{\Delta\pi} = ...
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Unusual High Ionizing Radiation Levels Detected in Eastern USA
I've been monitoring radiation levels using a Terra-P MKS-05 IP30 dosimeter and have observed some alarmingly high spikes that I cannot fully explain. I'd like to see if anyone may have some insights ...
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$\beta^-$ decay of $^{247}\rm{Cm}$ to excited states of $^{247}\rm{Bk}$
The nuclide $^{247}\rm{Cm}$ is only known to be an alpha emitter with a half life of $1.56\times 10^7$ years. In theory, it is also capable of $\beta^-$ decay to $^{247}\rm{Bk}$ with a $Q$ value of $...
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Why is radiation power defined at infinity?
According to Griffiths in chapter 11 , given a source of radiation enclosed by a sphere, the power passing through the sphere is
$$ P(r) = \oint \mathbf{S} \cdot d\mathbf{a} = \frac{1}{\mu_0} \oint (...
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How were luminous intensity changes for each EM frequency measured in the blackbody experiments of the late 19th c., which led to up to Planck’s Law?
If in today’s parlance it would be either ‘spectral density’ or ‘spectral radiance’ that was in fact measured then as opposed to ‘luminous intensity’ please feel free to clarify.
Kindly note that my ...
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