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What are plasmons?

A plasmon is a quantum of plasma oscillation, just like photon is a quantum of light radiation.

Plasmon is a quasiparticle resulting from the quantization of plasma oscillations.

Plasmons play a large role in the optical properties of metals. Light of frequency below the plasma frequency is reflected, because the electrons in the metal screen the electric field of the light. Light of frequency above the plasma frequency is transmitted, because the electrons cannot respond fast enough to screen it. In most metals, the plasma frequency is in the ultraviolet, making them shiny (reflective) in the visible range.

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Surface plasmons

Surface plasmons are those plasmons that are confined to surfaces and that interact strongly with light resulting in a polariton

Read more at http://en.wikipedia.org/wiki/Surface_plasmon

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Can the process of Pair Production be used as a source for energy generation in space?

Can the process of Pair Production

Creation of an electron and a positron by Pair...

Creation of an electron and a positron by Pair production. (Photo credit: Wikipedia)

be used as a source for energy generation in space?  Can Gamma Rays in space become the source for generating  energy using Pair Production process?  EM radiation >1.02 MeV enery, Pair Production is the dominant absorption process.

(Posted By Chintan Shah)

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GPS (Global Positioning System) Accuracy of Measurement

The 24 satellites that orbit the earth and define the Global Positioning System use
precision atomic clocks that are accurate to 1 x 10-9 s, or 1 nanosecond (1ns). A person on the earth, using their mobile phone, can usually “see” 4-12 of the 24 satellites at any one time.

An animation depicting the orbits of GPS satel...

An animation depicting the orbits of GPS satellites in medium Earth orbit. (Photo credit: Wikipedia)

The satellites are moving, relative to the surface of the earth, at 1.4 x 104 km/h.
a- Calculate  for one of these satellites,
Civilian GPS measurements have to be accurate at the level of 5-10m. How accurate must our knowledge of the clocks on the satellites be in order to achieve this level of accuracy in our position measurement?
[HINT: light signals are used by your phone and the satellites to perform the triangulation]
c-If we measure the passage of 1 day on earth using a clock that is identical to the clocks on the GPS satellites, how much time have the clocks on the satellites measured? What about for the passage of 2 days on earth? For this problem, it will be useful to apply the Binomial Expansion again

Mona asked

Thoughts on Higgs Boson

When it is not contested scientifically that change is a continuous phenomenon,how is that Higgs boson, if found,can be considered as the ultimate building block of matter.

Sure, it may prove a mathematically arrived conclusion… yet the contradiction remains.
An ever changing, at the same time, ever stable (because it is the ultimate one) is the contradiction.
One may find changing or divisible particle only…

(Posted by K.C. Muralidhar)

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