News tagged with permittivity
Permittivity
In electromagnetism, absolute permittivity is the measure of the resistance that is encountered when forming an electric field in a medium. In other words, permittivity is a measure of how an electric field affects, and is affected by, a dielectric medium. The permittivity of a medium describes how much electric field (more correctly, flux) is 'generated' per unit charge. Less electric flux exists in a medium with a high permittivity (per unit charge) due to polarization effects. Permittivity is directly related to electric susceptibility, which is a measure of how easily a dielectric polarizes in response to an electric field. Thus, permittivity relates to a material's ability to transmit (or "permit") an electric field.
In SI units, permittivity ε is measured in farads per meter (F/m); electric susceptibility χ is dimensionless. They are related to each other through
where εr is the relative permittivity of the material, and = 8.85… × 10−12 F/m is the vacuum permittivity.
For more information about Permittivity, read the full article at
Wikipedia.
This text uses material from Wikipedia and is available under the GNU Free Documentation License.
Invisibility cloaks may be just around the corner
In 1897, H.G. Wells created a fictional scientist who became invisible by changing his refractive index to that of air, so that his body could not absorb or reflect light. More recently, Harry Potter disappeared ...
Mar 04, 2011 |
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Beyond the looking glass...
While the researchers can't promise delivery to a parallel universe or a school for wizards, books like Pullman's Dark Materials and JK Rowling's Harry Potter are steps closer to reality now that researchers ...
Aug 13, 2009 |
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Storing a Lightning Bolt in Glass for Portable Power
(PhysOrg.com) -- Materials researchers at Penn State University have reported the highest known breakdown strength for a bulk glass ever measured. Breakdown strength, along with dielectric constant, determines ...
May 05, 2009 |
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Physicists continue work to abolish time as fourth dimension of space
(Phys.org) -- Philosophers have debated the nature of time long before Einstein and modern physics. But in the 106 years since Einstein, the prevailing view in physics has been that time serves as the fourth ...
Apr 14, 2012 |
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Researchers create “antimagnet” cloaking device
In what seems like one new cloaking device being discovered after another, researchers in Spain have modeled a device that they say can prevent magnetism from leaking out of a containment container and also prevent it from ...
Aug 05, 2011 |
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Portable breast scanner allows cancer detection in the blink of an eye
(PhysOrg.com) -- Professor Zhipeng Wu has invented a portable scanner based on radio frequency technology, which is able to show in a second the presence of tumours – malignant and benign – in the ...
Oct 27, 2010 |
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Optical surface states in magnetophotonic crystals
Using state of the art microfabrication technology to create periodic structures with high accuracy, Dr Baryshev and colleagues at the Toyohashi University of Technology, Japan, report the existence of so-called ...
Oct 26, 2010 |
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Invisibility cloak that generates virtual images gets closer to realization
(PhysOrg.com) -- In a twist on the concept of an invisibility cloak, researchers have designed a material that not only makes an object invisible, but also generates one or more virtual images in its place. ...
Apr 02, 2010 |
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IMEC shows optimizations for next-generation transistors
IMEC has achieved promising results in the race to scale CMOS to 22nm and below. The breakthroughs from its transistor scaling programs include a successful integration of the laser-anneal technique in a high-K/metal-gate ...
Jul 14, 2009 |
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Looking for water on Mars
NASA's Phoenix Scout Lander reached Mars on May 25,, opened a soils lab, and started looking for water. Phoenix uses a robotic scoop arm to deliver regolith samples to the suite of instruments aboard the Lander--with one ...
Space & Earth / Space Exploration
Sep 28, 2008 |
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Polymer electric storage, flexible and adaptable
(PhysOrg.com) -- The proliferation of solar, wind and even tidal electric generation and the rapid emergence of hybrid electric automobiles demands flexible and reliable methods of high-capacity electrical storage. Now a ...
Aug 20, 2008 |
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Invisibility cloak now within sight: scientists (Update 2)
(PhysOrg.com) -- Scientists at the University of California, Berkeley, have for the first time engineered 3-D materials that can reverse the natural direction of visible and near-infrared light, a development ...
Aug 11, 2008 |
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Using ground-penetrating radar to observe hidden underground water processes
To meet the needs of a growing population and to provide it with a higher quality of life, increasing pressures are being placed on the environment through the development of agriculture, industry, and infrastructures.
Space & Earth / Earth Sciences
Mar 20, 2008 |
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