# Introduction and key concepts

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## Introduction

Electrostatics is the study of electric charge which is static (not moving).

## Two kinds of charge

All objects surrounding us (including people!) contain large amounts of electric charge. There are two types of electric charge: positive charge and negative charge. If the same amountsof negative and positive charge are brought together, they neutralise each other and there is no net charge . Neutral objects are objects which contain equal amouts of positive and negative charges. However, if there is a little bit more of one type of charge than the other on theobject then the object is said to be electrically charged . The picture below shows what the distribution of charges might look like for a neutral, positively charged andnegatively charged object.

## Unit of charge

Charge is measured in units called coulombs (C) . A coulomb of charge is a very large charge. In electrostatics we therefore often work with charge in microcoulombs (1 $\mu$ C = $1×{10}^{-6}$  C) and nanocoulombs (1 nC = $1×{10}^{-9}$  C).

## Conservation of charge

Objects may become charged in many ways, including by contact with or being rubbed by other objects. This means that they can gain extra negative or positive charge. For example, charging happens when you rub your feet against the carpet. When youthen touch something metallic or another person, you feel a shock as the excess charge that you have collected is discharged .

Charge, like energy, cannot be created or destroyed. We say that charge is conserved .

When you rub your feet against the carpet, negative charge is transferred to youfrom the carpet. The carpet will then become positively charged by the same amount .

Another example is to take two neutral objects such as a plastic ruler and a cotton cloth (handkerchief). To begin, the two objects are neutral (i.e. have the same amounts of positive and negative charge).

Now, if the cotton cloth is used to rub the ruler, negative charge is transferred from the cloth to the ruler. The ruler is now negatively charged and the cloth is positively charged. If you count up all the positive and negative charges at the beginning and the end, there are still the same amount. i.e. total charge has been conserved !

Note that in this example the numbers are made up to be easy to calculate. In the real world only a tiny fraction of the charges would move from one object to the other, but the total charge would still be conserved.

The following simulation will help you understand what happens when you rub an object against another object.
run demo

#### Questions & Answers

How we are making nano material?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
research.net
kanaga
sciencedirect big data base
Ernesto
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
Bharti
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
Daniel
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
Maciej
characteristics of micro business
Abigail
for teaching engĺish at school how nano technology help us
Anassong
How can I make nanorobot?
Lily
Do somebody tell me a best nano engineering book for beginners?
s. Reply
there is no specific books for beginners but there is book called principle of nanotechnology
NANO
how can I make nanorobot?
Lily
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
s.
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
Tarell
what is the actual application of fullerenes nowadays?
Damian
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
Tarell
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
Virgil
is Bucky paper clear?
CYNTHIA
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
NANO
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Source:  OpenStax, Siyavula textbooks: grade 10 physical science. OpenStax CNX. Aug 29, 2011 Download for free at http://cnx.org/content/col11245/1.3
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