Questions tagged [electromagnetism]

Electromagnetism is the branch of science concerned with the forces that occur between electrically charged particles. Use this tag for anything related to electricity, electrical or magnetic fields (such as microwave radiation), etc.

Electro-Magnetic Force
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Electromagnetic force is one of the four fundamental interactions in nature, the other three being the strong interaction, the weak interaction and gravitation.

Electromagnetism is the interaction responsible for practically all the phenomena encountered in daily life, with the exception of gravity. Ordinary matter takes its form as a result of intermolecular forces between individual molecules in matter.

Electrons are bound by electromagnetic wave mechanics into orbitals around atomic nuclei to form atoms, which are the building blocks of molecules. This governs the processes involved in chemistry, which arise from interactions between the electrons of neighbouring atoms, which are in turn determined by the interaction between electromagnetic force and the momentum of the electrons.

James Clerk Maxwell
James Clerk Maxwell

Electromagnetism manifests as both electric fields and magnetic fields. Both fields are simply different aspects of electromagnetism, and hence are intrinsically related. Thus, a changing electric field generates a magnetic field; conversely a changing magnetic field generates an electric field. This effect is called electromagnetic induction, and is the basis of operation for electrical generators, induction motors, and transformers.

Electric fields are the cause of several common phenomena, such as electric potential (such as the voltage of a battery) and electric current (such as the flow of electricity through a flashlight). Magnetic fields are the cause of the force associated with magnets.

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Does tying a knot in a power cord provide any protection against lightning?

Some 20 years ago, when I was 11 or 12 years old, I attended a weekend 4-H camp about electricity. I recall one of the instructors there informing us that the cheapest way to protect our electronic equipment from lighting strikes was to tie 2 or 3…
Flimzy
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Are electric chairs powered by generators connected to the mains in the same building?

There's an episode in The Green Mile movie where the death row servicemen rehearse the upcoming execution that is done using an electric chair. One of them says (quoted from here): Roll on one. [pause] "Roll on one" means I turn the generator…
sharptooth
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Does Van Eck Phreaking work?

Does Van Eck phreaking perform as described, i.e. allow a person to observe what is being displayed on a given computer screen (notably a LCD) from a distance without having any physical connection to the machine being monitored, and without the…
Brian M. Hunt
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Can WiFi waves cause headaches?

I saw there was a question about the harmfulness of WiFi waves, but i'd like to focus on the claims that they can cause headaches specifically; not the cancer-claims. Numerous people come up with anecdotes about how they, or someone they know, get…
Wouter
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Is Vatican Radio causing childhood leukaemia?

It an ugly, long standing story in Italy: Vatican radio has huge antennas, not subject to Italian law, and the people living in the surroundings lament severe ailments such as leukaemia. The Santa Maria di Galeria transmitter site is the subject of…
Sklivvz
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Does never charging a laptop battery to more than 80% capacity increase its lifespan?

In relation to Does recharging a battery when it is only half-way dead decrease its life span? I read an article about Maximizing the lifespan of a laptop battery where Samsung puts it: Most battery damage occurs when the cells inside are at or…
Aske B.
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Can 'resonant frequencies' kill cancer cells?

According to some guy called Anthony Holland, you can kill cancer cells with resonant frequencies: "Cancer Research", Novobiotronics; "Shattering cancer with resonant frequencies: Anthony Holland at TEDxSkidmoreCollege", in which Holland presents…
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Could a single nuclear EMP kill 90% of Americans within one year?

From the latest doomsday scenario: At a U.S. House of Representatives hearing on October 12th, experts warned that the greatest existential threat to the country may come from the detonation of a nuclear EMP bomb. It could kill as many as 90…
Fizz
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Do Compact Fluorescent Lamps (CFL) create dirty electricity which can impact health?

According to this CBC Be Green report: 'CFLs [Compact Fluorescent Lamps] produce what is called "dirty electricity".' In an environment with dirty electricity, diabetics blood sugar will climb. It will drop again in a clean electricity…
Oddthinking
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Are electronic power consumption "smart meters" an invasion of privacy?

I've recently seen some commotion online about "smart meters," electronic power consumption meters that are replacing the mechanical meters in some areas. My understanding is that these meters have radio transmitters that broadcast each household's…
Carson Myers
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Can "Current Mohan" conduct high levels of electrical current through his body?

I saw this episode of Stan Lee's Superhumans featuring Raj Mohan Nair, also known as "Current Mohan". He seems to be able to conduct electric current through his body to power up household electrical appliances without suffering the adverse effects…
Question Overflow
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Fighting fire with electricity. Plausible?

The article "Fighting fire with volts: How water hoses could be replaced with electric wands" gives exciting news about possible new way of extinguishing fire, researched by Ludovico Cademartiri, Ph.D.: Scientists connected a 600-watt amplifier to…
Egle
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Are microwave hot-spots real?

So, this was originally a part of this question, but from the comments it seems like it might be beneficial to branch it. I have been told that the microwave left "hot spots" — areas in a fluid which were substantially(?) warmer than the…
cwallenpoole
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Can smartphone Apps detect EMF?

There are a couple of Android apps to detect EMF (for ghost hunting and for hazard-protection). I tried a free one which did not work. Some I can't seem to download. Has anyone tested them (against a fan, microwave or magnet, etc.) and see if it…
TheTechGuy
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Can defibrillation revive a flatlined patient?

Wikipedia notes that the technical term for flatline is asystole and adds this comment: Despite defibrillation commonly appearing on medical dramas as a remedy for asystole, it is usually not done when there is a total absence of electrical…
MrHen
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