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Questions tagged [electromagnetic-radiation]

Electromagnetic radiation (EM radiation, EMR, or light) is a form of energy released by electromagnetic processes. In physics, all EMR is referred to as light, but colloquially light often refers exclusively to visible light, or collectively to visible, infrared, and ultraviolet light.

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Will gamma radiation cause “thermal” decomposition of sodium bicarbonate?

I am conducting research for a new drug that contains powdered sodium bicarbonate, and the drug will need to be sterilized after placement into it's container/closure system. Typically, this is ...
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121 views

De-excitation of a molecule

In our chemistry lecture today on UV/vis-spectroscopy, we discussed the origin of colour in conjugated molecules due to electronic transitions from lower-energy molecular orbitals to higher-energy ...
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58 views

What is the relationship between emission and fluorescence?

A molecule exposed to a photon with some energy is put into an excited state, and emits a photon of some energy when it returns to ground state. The photon that provided the energy for excitation ...
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How much heat is created by absorbent-type sunscreens?

I have a friend who claims her dermatologist told her than sunscreen was what was burning her skin. (I think it's much more likely that her rash/burn was either a sunburn, a skin reaction to some ...
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488 views

Can visible light or infrared radiation excite electrons?

So the limit of ionizing radiation seems to be UV light. I'm wondering if IR light or Visible light can excite the electrons in an atom. It has to do with the difference in energy level right? So ...
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2answers
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How much ionising radiation is released during an atomic blast?

I've been looking for how much ionising radiation is produced during an atomic blast (as a percentage). I have seen a claim of 5% of the energy in an atomic blast is ionising energy (Wikipedia), but ...
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70 views

Quantization and Bohr's model

According to quantization it's said that emitted or absorbed energy is quantized. Then, when it's said in bohr's model an electron changes its orbit (Let's say it goes to a higher energy shell from $...
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199 views

Can gas be made to block radiation better?

Can any gas block radiation? I ask this because I would like to know if the properties of any gas element would chemically react differently with radiation from adding an electrical current. This ...
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29 views

Reaction of electromagnetic radiations with the air pollutants [closed]

My friends, who are working on an IoT based technology project, explained their idea to me which is roughly like reducing air pollution by converting pollutants to oxygen ($\ce{O2}$) in any reaction, ...
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191 views

Electromagnetic energy to Chemical energy [closed]

How can electromagnetic energy (photons) be efficiently converted to chemical energy? For instance, can water be efficiently split to hydrogen and oxygen using solar energy? As we are running out of ...
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1answer
26 views

detecting/tracking nano particle [closed]

I am new to nano-sized particles and conducting a very simple experiment using nano particles. In my experiment I have nanomagnetic particles inside water and they are moving due to applied magnetic ...
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2answers
62 views

How do IR spectrometers produce light spanning the entire infrared spectrum?

An IR spectrum covers thousands of wavenumbers, typically $\sim 4000$ to $\pu{400 cm-1}$. How are the spectrometers able to generate different wavelengths of light covering this entire range of ...
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When precessing nuclei absorb electromagnetic radiations, am I supposed to consider the wave nature or particle nature of light?

I decided to peek into the NMR section of my spectroscopy book, and I found out lots of interesting stuff. And along with the interesting stuff, I did come along some stuff that I didn't understand. ...
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74 views

Selective bond breaking

Can a specific bond be broken by an engineered energy wave corresponding to the bond length? For example, can we break the $\ce{C-N}$ bond and not the $\ce{C-H}$ in a hydrocarbon chain?
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Photoelectric effect and kinetic energy

According to my textbook, electrons which are emitted due to the photoelectric effect have kinetic energy given by: $$KE_{electron}=h\nu-h\nu_0$$ Where $\nu_0$ is the activation frequency of the metal....
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What is the quantum mechanical explanation of X-ray diffraction?

One topic in crystallography that I've found a surprising dearth of information on is what the fundamental interaction behind the interaction of the X-ray and atom. Pretty much every book just treats ...
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Why can UV light initiate a reaction between hydrogen and chlorine gas?

Can someone explain me how does UV light help combine chloride gas and hydrogen to produce hydrochloric acid? $$\ce{Cl2(g) + H2(g) -> 2HCl(g)}$$
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103 views

How does magentic field change spin values of a proton or electron? [closed]

I am asking this in context of NMR. Firstly I wanna say that I thought that spin values of a proton or electrons were intrinsic. I didn't know that you can change spin states from one value to another....
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Microwaving a glass of water, what happens?

Most of us here would already know the simplified idea behind microwaving food: Microwave radiation hits the water molecules present in food, which excites them and causes 'em to vibrate rapidly in ...
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Formulae for energy of photon (E=hf and E=hv)

I have seen the energy of a photon given by the formulas: $$E = h \cdot f \tag{1}$$ Where $E$ = energy of the photon, $h$ = Planck's constant, $f$ = frequency of radiation (Source: BBC article) I'...
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76 views

Are the $+\leftrightarrow+$ and $-\leftrightarrow-$ methanol rotational transitions dipole-allowed?

I am quite confused about the origin and justification of the rotational selection rules of methanol, and I would appreciate any help or references. As far as I understand, there are three irreducible ...
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0answers
80 views

Grapes in a Microwave - Experiment

I am considering attempting an experiment in which one puts two, almost severed, halves of a grape in a microwave with a glass over it. To my knowledge so far, the grape halves act as focal point for ...
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2answers
589 views

Stability of Bohr Orbits

In class we had been taught that Rutherford's model was unsuccessful because it failed to show that the orbits are stable because the electrons would lose energy because of electromagnetic radiation. ...
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2answers
505 views

How do EM waves cause molecules to rotate, move, and cause electrons to move up energy levels?

Atoms can absorb electromagnetic waves to cause electrons to jump up energy levels, when electrons go down energy levels they release a photon. But how do EM waves cause atoms to rotate, and vibrate?
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Can sunlight and its heat create a caustic or toxic substance from coconut oil on human skin? [closed]

I heard that story quite often, if it's true, how does it work? Notice that I’m not talking about using coconut oil as a sunscreen (it’s another topic) but about the action of the sun on the oil and ...
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1answer
75 views

Substances that pass visible light but absorb microwaves

Specifically, the substances should be water-miscible or water-soluble, but not water itself. Additionally, they should be absorptive but not opaque.
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1answer
304 views

What is the reason why protons and electrons do not collide?

can someone give me an intuitive picture of why electrons don't collide with protons? I know that electrons move in a sort of cloud, which is our 'orbital', and that they mainly behave like ...
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355 views

Burning Of Coal and Black Body Radiation

Coal burns with a red glow. What is the ignition temperature of coal? If it is T, and I take another substance which has melting point quite above T, and heat it to T, Will it also emit red light?
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227 views

What is generally meant by distinct line spectrum?

In a single hydrogen atom the electron is excited to 6th orbit. The book says maximum 5 distinct spectral lines are possible when the electron comes to the ground state. Looks like they have only ...
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3answers
2k views

Can gamma radiation cause transmutation?

In irradiation of food for sterilisation, is gamma radiation absorbed by the food? If so, can it theoretically cause production of radioisotopes? Or does it ionise atoms in the food?
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1answer
127 views

What chemical properties that allow for colour exist in the dark?

Of course if there's no light around, there's no colour that you can see. On the other hand, the wall must have some property that makes it be blue. That property is still there in the dark. — ...
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2answers
1k views

Transmission, absorption, and reflection of light

My understanding is: when light hits an object, it can do one of three things: transmit through the object, be absorbed into the object, or reflect from the object. However, I have also learned that ...
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1answer
55 views

Anion formation in an alpha particle-neutral atom interaction?

How can an alpha particle/beta particle/gamma rays interacting with a neutral atom lead to an anion forming? Because i can see how they cause loss of electrons leading to cations forming, but how can ...
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0answers
37 views

Is there a material that turns from being electrically conductive to non-conductive irreversably upon exposure to some form of radiation?

For my project I am looking for a material which can turn from being electrically conductive to nonconductive (has to be irreversible) upon exposure to electromagnetic radiation (say UV). I tried ...
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66 views

Radiating chemical suggestion?

Given a flat and thin object laying on a table, such as a small piece of silver paper or a small piece of cardboard, I want to find a way to detect which face of it is facing up. The solution should ...
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2answers
2k views

Is Neutron radiation considered electromagnetic wave?

I'm confused because gamma rays are classified as an electromagnetic wave. But why is neutron radiation not considered electromagnetic wave? I know Alpha and Beta, as well as positron and proton, is ...
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0answers
29 views

Why are certain substances clear/invisible? Can we create invisible objects? [duplicate]

This is more so a question of how light interacts with matter. For example, why are substances like oxygen generally invisible? If the light hitting the molecules were absorbed, it would appear black, ...
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1answer
2k views

Is there any difference between de-Broglie wavelength and the wavelength of normal waves?

Is de-Broglie wavelength different from wavelength of waves such as electromagnetic waves? If yes, they differ in what respect? And can we use the formula of wavelength of light ($c=v\lambda$) to ...
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1answer
581 views

Are photons ejected from atomic nuclei?

I have heard that electrons absorb or eject photons when transitioning from one orbital to another. Is this correct? Can atomic nuclei eject photons?
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2answers
341 views

Why does a mixture of siloxene and cerium(IV) sulfate luminesce?

I performed an experiment where siloxene and cerium(IV) sulphate were mixed together: when I did so the mixture produced an orange-yellow glow. Why does it glow? What is it about the two chemicals in ...
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1answer
209 views

Wavelengths of the visible spectrum

Why is data about wavelengths of different colors and the visible spectrum in general so different in different sources? On Wikipedia, the numbers differ by up to $\pm\mathrm{30~nm}$.
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3answers
9k views

Are there non-transparent gases?

Are there gases that are not transparent at room temperature (i.e. at temperature below the point where the substance starts to radiate visible light due to heating)?
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3answers
174 views

In spectroscopy, is it possible for the sample to be excited multiple times?

The context of my question is rotational spectroscopy (using microwave radiation), where there is the $J = \pm 1$ selection rule. The way I understand spectroscopy is that the sample is irradiated ...
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1answer
254 views

Can one figure out an optical absorption spectrum from EPR data?

I'm wondering if it's worthwhile for me as an optical spectroscopist to read up a bit on EPR. Do EPR signals reveal where, in terms of wavelength, features in the optical spectrum can be expected to ...
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1answer
255 views

Is a microwave oven dangerous? [closed]

If we take a look at the electromagnetic specter, microwave wavelength is higher than infrared, which means its energy is very small. To break chemical bonds, the energy required is 100-1000 kJ/mol, ...
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1answer
478 views

Radiation in space and its effects on chemical reactions?

I know that one current area of research is ways to protect astronauts from ionizing radiation when they venture out of the atmosphere of Earth, but would that same ionizing radiation be a cause of ...
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1answer
135 views

How does radiation facilitate the formation of tetravalent iron?

In reading the article abstract What Oxidation State of Iron Determines the Amethyst Colour?, the author states that in regards to the gemstone amethyst, from clear quartz: The crystal was ...
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2answers
76 views

Frequency, the only real characteristics of electromagnetic radiation ??

My book says: frequency is considered as the only REAL characteristics of electromagnetic radiation, because it is unchangeble if the radiation comes up with some other environment, while the ...
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1answer
8k views

Why is beryllium transparent to x-rays?

Beryllium has other fancy applications. It is transparent to x-rays, so it's used in the windows of x-ray tubes, which need to be strong enough to hold a perfect vacuum, yet thin enough to let the ...
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227 views

How does UV affect skin colors in dark-skinned people?

Skin color is one of the things one would rather not ask anything about! Only in humans, it can vary from very dark brown to pale pink. In darker-skinned people, the color is mainly due to melanin, ...