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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469 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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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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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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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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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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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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1answer
577 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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850 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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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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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. — Mike W. ...
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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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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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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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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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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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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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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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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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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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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
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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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How can I interpret the colour of flames in terms of spectral series?

I saw different colors of fire burning different metals. But how does this work? The Balmer series requires electrons to drop back down to n = 2. But, not all alkali metals have empty space in their ...
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1answer
244 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, ...
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How do sunscreens protect the skin from UV rays?

I was unsure to the largest extent about whether I should post this question in chemistry Q & A or bio Q & A until I just read that sunscreens "absorb" UV rays, not allowing the most of those ...
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Why they have different flame colour?

At school, I learnt about the metal and their flame colour. Here's my observations. $\ce{K^+}$- Lavender $\ce{Ba^2+}$- Yellow-Green $\ce{Ca^2+}$- Yellow-Red $\ce{Li^+}$- Flame Red $\ce{Na^+}$- ...

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