Electrostatics

ELECTROSTATICS

Submitted by: 21 Daphne Jaime

22 Juliene Legaspi

23 Karen Lustanas

24 Anjanelle Madlangsakay

IV- St. Angela

A. ELECTRO STATIC “ELECTRICITY AT REST”

•Static electricity involves electric charges. Electric charges arise from particles of atoms. •The charges of these particles contribute to the overall charge of any object that contains them. •Molecules – made up of atoms•Atoms – made up of positive and negative charges

B.

Atoms have zero net charge,

because they have equal number

of electrons and neutrons.

Protons in the nucleus attract

the electrons and hold them in

orbit. Electrons are attracted to

protons but electrons repel other

electrons.

C. KINDS OF CHARGES

•Positive charges-comes from having more protons than electrons•Negative charges-comes from having more electrons than protons.•Uncharged- Equal number of protons and electrons

D.

E. FACTS

•Every atom has positively charge nucleus surrounded by negatively charge electrons.•All electrons are identical; each have the same mass and the same quantity of negative as every other electron.

F. METHODS OF CHARGING 1. Charging by Friction

•Transfer of electrons between the two objects that are rubbed together. •Material losing electron is positively charged and material gaining electron is negatively charged. •Amount of gained and lost electron is equal to each other.

.

Triboelectric series

- The ordering of substances according to their affinity for electrons

2. Charging by Induction

•Method used to charge an object without actually touching the object to any other charged object.

•The charged object is never touched to the object being charged by induction.•The charged object does not transfer electrons to or receive electrons from the object being charged.•The charged object serves to polarize the object being charged.

Charging by Conduction

Charging by conduction involves the contact of a charged object to a neutral object.

In contrast to induction, where the charged object is brought near but never contacted to the object being charged, conduction charging involves making the physical connection of the charged object to the neutral object. Because charging by conduction involves contact, it is often called charging by contact.

G. THE ELECTROSCOPE

. Illustrates induction.

.A device that is capable of detecting the presence of a charged object.

1. KINDS

LAW OF CHARGESA. CHARLES A. COULOMB- relationship between attracting or repelling charged bodies.B. Depends on 2 things: 1. Their charges 2. The distance between them C. Laws of Charges 1. Unlike charges attract 2. Like charges repelD. Charges can be created and destroyed, but only in positive-negative pairs

COULOMB’S LAWA. Discovered by French Physicist Charles Coulomb in the 18 th century.B. Force F between two charged spheres is inversely proportional to the square of the distance d. C. Force is directly proportional to the charges Q1 and Q2

D. FORMULA•d is the distance between the charged particles•Q1 and Q2 represents the quantity of charge of the particles.•k is the proportionality constant.•Unit of charge is called COULUMB (C)•1 C is the charge of 6.24x1018 electrons.• k is a very large number. Rounded off, it equals to 9.0x10 9N•m2/C2

CONDUCTORS AND INSULATORS

A. CONDUCTORS•Materials which contain movable charges that flow with minimal resistance.•Conduction- transfer of electrons from a charge object to another by direct contact. •Induction- movement of electrons to one part of an object by the electric field of another object.•The outermost electrons are loosely bound and are free to travel around.•When the conduction and valence bands overlap the atom is a CONDUCTOR and allows the free movement of electrons•EXAMPLES: Au, Ag, Cu, Al, Fe, Hg, bronze, dirty water

B. INSULATORS•Material which few or no movable charges which flow with extremely high resistance.•The electrons are much more tightly bound to atoms and are not free to flow.•Polarization- electric charges can shift slightly to one side when there is a change nearby•When there is a large energy level gap between the conduction and valence bands, the atom is INSULATOR; it traps electrons.• EXAMPLES: glass, rubber, oil, plastic, air, diamond, pure water