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Electricity: I was wondering, whether we can pass electricity through air over a distance of 100 meters or so as electricity means the flow of electrons and we have seen the discharge or movement of electrons in a cathode ray tube

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The cathode ray tube has had the air pumped out. Electrons scatter off oxygen and nitrogen molecules so if you fired an electron beam in air it would be scattered in a short distance. The distance would depend on the beam energy, but it's a lot shorter than 100m. The range of electrons from beta radiation in air is around a metre.

You could argue that lightning is the conduction of electricity through air, though I don't think anyone has ever seriously proposed this as a method for passing electricity through air in domestic applications.

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  • $\begingroup$ That's pretty interesting if the electrons can travel through air, there is n resistance so he work done to pass electricity would be very less and again we can use large electromagnetic fields to pass those electrons. Is it so? $\endgroup$ – Prashant Jul 4 '14 at 7:40
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    $\begingroup$ @Prashant: well yes, that's how lightning works. However, apart from being an exceedingly dangerous way to conduct electricity through air it would be exceedingly inefficient as you'd waste energy ionising the air. $\endgroup$ – John Rennie Jul 4 '14 at 7:58
  • $\begingroup$ Thank You @John Rennie that was useful but if its through vacuum than there is no need for ionising the air so even if it wouldn't help to supply electricity it migh help in some other ways :) $\endgroup$ – Prashant Jul 4 '14 at 9:49
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In principle, it is possible, using, e.g., high-current relativistic electron beams - please see, e.g., the review http://arxiv.org/abs/physics/0409157 . @John Rennie offers reasonable arguments, but the very real problems he mentions can be overcome - I don't have time to describe the specific mechanisms (see the review). In experiments, propagation length in the atmosphere of at least 20 m was achieved (30 years ago). Let me emphasize that the relevant research is done mostly for weapons development, not for power transmission, and the results are often classified, so I cannot be sure about the maximum propagation length currently achieved.

Let me also note that it may be easier to use electromagnetic radiation (visible or, say, microwave) for power transmission in the atmosphere. It's for you to decide if this is relevant to your question.

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An radio frequency is essentially an alternating current passing through the air. It can be omni-directional, narrow beam, or wide beam. A radio frequency in narrow beam theoretically can transfer power from one point to another.

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There have been numerous demonstrations by Nikola Tesla, about electricity passing through air. He showed his toy sized boat being operated wirelessly with the current he called Alternating. He showed how he ran a motor with its circuits being wireless. And another example his Tesla Coil.

Nowadays, the HAARP technology in US is trying to implement that, and trying to send electricity through air into the sky to change the weather or other places where it could be consumed. Scientists have tried to send electricity through air to Japan. And i think, if this "flow of electrons can take place in conducting solids and liquids, then why not even in atmosphere?

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  • $\begingroup$ I suggest take a short gooogle search about the topics maxwell-equation, induction and similar. Your hyphoteses are accepted theory since more as a century, only you don't know it. $\endgroup$ – peterh Feb 22 '17 at 7:54

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