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Explain a method to create Uniform Electric Field.

Relativistic electromagnetism (fig. 1): Two op...
Two oppositely charged plates produce a uniform electric field even when moving.(Photo credit: Wikipedia)

 

The simplest method of creating a uniform electric field in a region is to keep two  equally charged thin plain metal sheets of opposite charge parallel to each other. As you can see from the derivation for electric field due to a plain sheet of charge, the electric field due to a plain sheet of charge is independent of distance (provided the distance is not large compared to the dimensions of the plain sheet of charge).

 

So, if you keep two plain metal sheets of same charge densities but opposite kind of charge, we get a fairly good uniform electric field in between the plates.

 

At regions close to a uniformly charged thin sheet also we get a uniform electric field, but as distance increases it may tend to become non uniform.

 

What is charge basically?

It may be rather silly but still I’m really curious to know about this.  What is charge basically?  I’m tired of reading and hearing charge is an inherent property of matter,  it is that which causes electric field etc.

 

Asked Sudha

 

Answer:

 

First of all, I would like to tell that I am interested mainly in such questions which are branded silly. But many of those silly branded questions are not so silly.

 

Charge is defined in intermediate Physics as below

 

“Electric charge is the physical property of matter that causes it to experience a force when close to other electrically charged matter. “

 

The concept of electric field was introduced by Faraday to explain how two charges exert force on each other without physical contact. A charged particle (and also a time varying magnetic field) produces an electric field.

 

English: Field of a positive point charge. Thu...

 

 

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?

Asked Gowtham

KS Samy answers:

“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.”

An interesting question from electrostatics

Two equal negative charge -q are fixed at the point (0,a) & (0,-a) on yhe y-axis. a positive charge Q is released from rest at the point (2a,0) on the x-axis. the charge Q will execute oscillatory motion how?

Asked Kritika

Ionizing Power of alpha and beta particles

Which has greater ionization power alpha or beta?

 

(Question received via speak pipe – a facility for the visitors to ask questions orally, if you have a mic)

 

Answer:

 

Alpha particles have greater ionization power as they have two units of positive charge and 4 units of mass, whereas beta has only one unit of negative charge and negligible mass as compared to alpha.

 

English: Diagram of an alpha particle with notes.

 

Current Carriers and conduction

1. Do the protons flow when current flow?
2. In case of semiconductor do the holes flow?

Animesh asked

Answer:

Atom 3D Model

In metallic conductors, free electrons are the current carriers, i.e, it is due to the motion of the free electrons that conduction takes place in a metallic conductor. The protons do not move as they are inside the nucleus and bound by strong nuclear forces. It is the electrons of the outermost shell of the atom which are least bound to the atom, flow and cause conduction

In semiconductors the current carriers are free electrons and holes.

What are holes?

Holes are actually vacancies created when an electron is freed from a bond. It is assigned a positive charge. When a potential difference is applied across a semiconductor, the free electrons move towards the positive terminal as in the case of a metal. The bonded electrons also move towards positive terminal from vacancy to vacancy and this causes the holes  t move towards the negative terminal.

 

Misconceptions on Electric Potential

We know that the potential developed at a point by a charge is the negative of the work done to bring a unit charge at that point from infinity. But how does a conducting plate develop a potential? what is the work done?

Answer:

I can smell some misconceptions in your question. It is better to revise the question after revising the topic on Elelctric Potential thoroughly.

3D Frenzy x Electric Fields

Electric potential at a point is defined as the work done per unit charge in bringing a positive test charge from infinity to that point against the electric field and without any acceleration.

When a conducting plate is charged, it is raised to some potential. Only to bring the first point charge to the plate, the work done is zero, but afterwards, repulsion is developed between the charge brought and the charge already present on the plate and therefore work is required to be done to increase the charge on the plate.

(Please revise the portions well and review the question asked)

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