# Tagged Questions

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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### Radiation from home heaters [closed]

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.
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### 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. ...
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### 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 ...
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### 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 ...
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### 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), ...
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### 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, ...
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### 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 ...
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### 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 ...
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### 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 ...
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### 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 ...
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### 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 ...
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### 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 ...
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Physically, what does it mean when people or objects are contaminated with radiation? Is it because they actually carrying heavy metal particles?
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### 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 ...
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### 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 ...
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### 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 ...
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### 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: ...
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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 ...
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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, ...
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### 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: ...