Static electricity is the study of charge at rest. Static electricity also called “Electrostatics”
Charge
Charge is the particles carry either positive particle or negative particle
Origin of Charges
When body rubbed cause the atoms to loose or gain electron which are revolve around atomic structure result causing the body to become charged. Due to that reason it tends to cause;
(a)
Plastic materials are rubbed on a
cloth/hair attract dust and small pieces of paper
(b)
Particles of wheat are attracted to
amber.
(c)
The moving parts of machinery, car
tyres, and vehicle bodies they attract light particles
(d)
Ebonite rubbed with fur/cloth attract
dust and small pieces of paper
(e)
Glass rubbed with silk attract dust
and small pieces of paper
(f)
Polythene rubbed with fur/cloth
attract dust and small pieces of paper
(g)
Polystyrene rubbed with fur/cloth
attract dust and small pieces of paper
(h)
Perspex rubbed with woolen cloth
attract dust and small pieces of paper
(i)
Cellulose rubbed with woolen cloth
attract dust and small pieces of paper
(j)
Some clothes cling to the body
(k)
Comb rubbed with sleeve attract piece
of paper
(l)
crackling noise while remove nylon
cloth
Types of Electric Charges
There are two types of charge include
i.
Positive charge (+)
ii. Negative charge (-)
Positive charge
Positive charge is a charge acquire when an object loose electron from its atomic structure
Negative charge
Negative charge is a charge acquire when an object gain electron
from its atomic structure
Nb:
i.
Electrons are revolving around the
nuclear
ii.
Electrons are moved from one atom to
another
iii. Protons never move from one to another atom
Charge acquired after rubbed
|
Materials |
Rubbed with |
Charge acquired |
|
Ebonite |
Fur/cloth |
Negative |
|
Glass |
silk |
Positive |
|
Polythene |
Fur/cloth |
Negative |
|
Polystyrene |
Fur/cloth |
Negative |
|
Perspex |
Woolen cloth |
Positive |
|
cellulose |
Woolen cloth |
Positive |
|
Plastic |
Cloth/dry hair |
Negative |
Fundamental law of electrostatics
The fundamental law of electrostatics which states that
“Like charges repel, unlike charges attract
each other”
Like Charges repel
Unlike Charges attract
Also is called fundamental law of static charges or first law of electrostatics
Charging
Charging is the process whereby material loose or gain electrons
OR
Charging is the process of either adding or removing charged electrons from a body
Methods of Charging
There are three methods as
i.
Rubbing or friction method
ii.
Conduction or contact method
iii. Induction method
Friction Method
When you rub two objects the one which his outer most shell weak
bound will lose and the one has sparsely electron gain the electron. Due to
that electrons shift from one object to another and tend to gain one to become
negative charged and lose one become positive charged
For Example
(a)
A polythene rod rubbed with fur
becomes negatively charged. Rubbing results in the transfer of electrons from
fur to the polythene rod.
(b) Fur becomes positively charged because some of its electrons are transferred to the polythene rod. The polythene gains excess electrons and hence it becomes negatively charged.
Contact Method
When charge and uncharged body contact the charge always move from charged body to another because like charge repel and unlike charge attract.
Consider the two charged body (y) and uncharged body (x)
Contact two bodies
Since like charge repel each other positive charge will shift/migrate from y to x
Separate them immediately
Now uncharged (x) became positive charged
Induction Method
When two body charge and uncharged body keep near, charged body
causes the other body to gain opposite charges to the one of the charging body.
Consider the two charged body (x) and uncharged body (y)
Place x near y
Since like charge repel, unlike attract each other negative charge
will pull positive and push negative charge.
Touch y to allow movement of electrons to ground. The
movement/flow of electrons to ground is called Earthing.
Now uncharged (y) became positive charged
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