Electric Charge & Static Electric Charge & Static Electricity 20.1Electricity 20.1

Chapter 20 ElectricityChapter 20 Electricity

What produces a net What produces a net electric charge?electric charge?

• Electric Charge = property that causes subatomic particles such

as protons and electrons to attract or repel each other

• Protons have positive charge (+)

What produces a net What produces a net electric charge?electric charge?

• Electrons have negative charge (-)Electrons have negative charge (-)

• Ex. Electric charge = lightning bolt Ex. Electric charge = lightning bolt or static clingor static cling

• An XS or Shortage of electrons produces a net electric charge- ions

What determines whether an What determines whether an electric force is attractive or electric force is attractive or repulsive?repulsive?

• Electric Force = the attraction or repulsion between electrically

charged objects • Like charges repel

• Opposite charges attract• Double electric charge will

double the electric force• In an atom Electric forces are

stronger than gravity = chemical bond

What determines the strength of What determines the strength of an electric field?an electric field?

• Electric fieldElectric field = is the space around = is the space around an object with an electric chargean object with an electric charge

• The strength of an electric field The strength of an electric field depends on:depends on:

• The amount of charge that The amount of charge that produces the fieldproduces the field

• On the distance from the chargeOn the distance from the charge

What are three ways in which What are three ways in which charge is transferred?charge is transferred?

• Charges can be transferred byCharges can be transferred by • Friction = Ex. Rub balloon on Friction = Ex. Rub balloon on

hair… Hair gives up Electron hair… Hair gives up Electron becoming (+) and balloon (-)becoming (+) and balloon (-)

• Contact = Van de Graff Contact = Van de Graff Generator — a charged metal Generator — a charged metal

sphere causes hair to repel each sphere causes hair to repel each otherother

• By Induction = Ex. When you By Induction = Ex. When you walk across a carpet & touch walk across a carpet & touch

door knob get a shock…door knob get a shock…

How does a static How does a static discharge occur?discharge occur?

• Static discharge is the shock you Static discharge is the shock you feel when you touch a door knob.feel when you touch a door knob.• Static discharge occurs when a Static discharge occurs when a pathway through which a charge pathway through which a charge

can move forms suddenly.can move forms suddenly.• When the gap between door and When the gap between door and

finger is small. finger is small. • Lightning is the same but more Lightning is the same but more

dramaticdramatic