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## expression for magnetic moment of the electron

An electron is moving with velocity v in an atom with orbital radius R.  Derive the expression for magnetic moment of the electron.

## Magnetic field due to current

A spinning electron creates a magnetic field.But what about an electron inside a current carrying wire electron is spinning around its axis and revolving in loop,both simultaneously.So,what if both the situations contradict (both magnetic fields are in opposite direction ).net M.F. should be zero then. I mean what is the fate of electron in a current carrying wire with respect to its spin?

## Electric potential due to a dipole

If a point lies at a distance x from the midpoint of the dipole the electric potential is?

If the distance x is along the equatorial plane (a plane passing through the midpoint and perpendicular to the axis), the potential will be zero.

Please clarify what did you mean.

## Current Electricity – Drift Velocity based numerical

Two different wires X and Y of same diameter but different materials are joined together in series     across a battery . If the number density of electrons in X is  twice that in Y . Find ratio of drift velocity of electrons in two wires .

In series combination, the current is the same.

I = nAev

=> n1v1 = n2 v2

=> v1:v2 =n2:n1

## 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.

Surface plasmons

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

[gview file=”http://www.optics.rochester.edu/workgroups/novotny/courses/OPT463/plasmonss.pdf”]

## Why there is no magnetic field around a disconnected copper wire

Moving electrons produce magnetic field right? Electrons on earth are moving at an average of 27.83m/s due to earths rotation plus 30m/s due to earths revolution and may be more due to sun’s revolution and our galaxy’s revolution.
since there is no absolute motion, how can we tell if electrons are moving?
If the electrons are moving, anyway, why is there no magnetic field around a disconnected copper wire?

## Why protons and electrons do not collapse and cancel?

According to Physics opposite charges always attract But in an atom the distance between nucleus and electrons are small then why electrons didnt combined with protons? protons and electrons have opposite charges.But why they didnt combined each other?

“Good question,, both sub-atomic particle have certain mass and energy,, we also know that it,, there is electrons revolved an nucleus and their corresponding energy level,, so that it don’t care their charges.. only arrange respect that energy,,,,

the minimum distance between nucleus and orbital electron have minimum energy, as well as large distance it as more energy.”

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