Chapter 3 PowerPoint: Electricity (stopped pg.11)

electricity concerns the distribution and movement of electrons, has little to do with

positively charged protons locked within the atomic nucleus

Electrostatics

study of electric charges that are fixed (at rest) and the forces between them

Law of Repulsion

attraction

• Like charges repel

• Unlike charges attract

Inverse Square Law

Force between two charges directly proportional to product of their magnitudes and inversely proportional to square of distance between them

• I₁ / I₂ = D₂² / D₁²

(Law of Distribution)

Charges reside on external surface of solid

conductors

(Law of Distribution)

Charges spread equally throughout in

nonconductors

(Law of Concentration)

Greatest concentration of charges will gather at

sharpest area of curvature

(Law of Concentration)

On a cylindrical wire, ______ are equidistant from each other

charges

(Law of Movement)

Only ________ charges move along surface of solid conductors

negative

Methods of Electrification

• Friction

• Contact

• Induction

Friction occurs when

one object is rubbed on another

Contact occurs when

two objects touch

Static discharge

releases excess energy as light photons

Induction

process of electric fields acting on one another without physical contact (ex. lightning)

Classes of electrical materials

• Conductors

• Insulators

• Semiconductors

• Superconductors

Distance between conduction band and valence electron shell

band gap

Closer the band gap to the valence shell,

the easier it is for electrons to flow (conduct)

Further the band gap to the valence shell,

the harder it is for electrons to flow

Electrons lose energy as

heat

Electrodynamics

the study of moving electric charges

Electric charges will move when a _______ exists

potential difference

Electrons move from areas of

high to low concentration

Electron Flow

Negative Pole to Positive Pole

Conventional Electric Current Flow

Positive Pole to Negative Pole