Chapter 6 – Electricity - PowerPoint Presentation

Slide1

Chapter 6

– ElectricitySlide2

6.1 Electric Charge

Positive and Negative Charges

Matter is composed of

_______

Atoms are composed of

protons, neutrons and electronsThe amount of positive charge on a proton is _____ to the amount of negative charge on an electronAtoms have _______________ (electrically neutral)Amount of electric charge is measured in ________ (C)6,250 million billion protons in 1 C of electric charge6,250 million billion electrons in -1 C of electric chargeCoulomb's Law: Like charges _____ and opposite charges _______.

Atoms

equal

no electric charge

coulombs

repel

attractSlide3

The difference between the # of protons and the # of electrons determines an object’s

___________;

therefore

(-) charged obj. have

______

electrons.(+) charged obj. have ______electrons.Obj. are charged by the _______of electrons.electric chargemorefewer

transferSlide4

Transferring Charge

Electrons are

_______________

to some atoms and molecules than others

Some atoms can

_______electrons more easily than othersLeads to an buildup of electrons on other substances (excess negative charge)  _____________bound more tightly

transfer

Static electricitySlide5

STATIC ELECTRICITYSlide6

Law of Conservation of Charge

Charge can be

_________

from object to object, but it

_______

be _______or _________transferredcannotcreateddestroyedSlide7

Charges Exert Force

The force between electric charges depends on

________

between charges

________

of charge_____DistanceAmountMass Slide8

_______________

have similar properties.

On this scale gravity dominates!

Gravitational ForcesSlide9

Comparing Electric Forces and Gravitational Forces

Force of gravity is much

______

than electric force

Electric force between a proton and an electron in a hydrogen atom is about a thousand trillion trillion trillion times larger (1039 X) than the gravitational force between the same particles.Chemical bonds in molecules are due to _______ forces between atomsMuch larger than the ___________ forces between the atomsweakerelectricalgravitationalSlide10

On this scale

___________

dominates

!

electrical forceSlide11

Electric Fields

Surround every electric charge and exerts the force that causes other electric charges to be

_________

or

________.

Do not need to be ________ to exert force on each otherAny charge that is placed in an electric field will be ______ or _______ by the field Electric Field Near Negative ChargeElectric Field Near Negative Charge

attracted

repelled

touching

pushed

pulledSlide12

Conductors and Insulators

Conductor

Material through which

____________________

Best electrical conductors are

________Conductors have _____ resistance?InsulatorMaterial in which electrons are ____________________Electrons are held ______________ that make up insulatorsBest insulators are _____ , ______ , ______ and ________.Insulators have a _____ resistanceelectrons move easily

metals

low

not able to move

easily

tightly to atoms

glass

plastic

rubber

ceramic

highSlide13

Conductors and InsulatorsSlide14

Types of Charging

Charging by Contact

The process of transferring charge by

_________

or

________.Also called charging by ___________Charging by InductionThe _______________ of electrons on a _________ object caused by a _______ object

touching

rubbing

conduction

r

earrangement

neutral

nearbySlide15

LightningSlide16

6.1 Summary

2 types of electric charges are

(+) & (-).

Like charges

repel

, unlike charges attract.On molecular level, electric force is stronger than gravitational forceElectric force acts through electric fields.Electric fields surround charged objects. Any charged object that enters a region with an electric field experiences an electric force.Electrons move easily through conductorsElectrons do not move easily through insulatorsSlide17

6.2 Electric Current

Current and Voltage Difference

________________

: the net movement of electric charges in a single direction

Measured in

_________ (A)1 ampere = __________________________ A voltage causes charges to move, which in turn produces a _______.A circuit must be ______ for a current to be produced.Electric currentamperes

1 Coulomb of electric charge

current

closedSlide18

A charged object has electric PE due to its

position

in an electric field.

Potential difference

or ________ is the difference in electrical PE per unit charge.SI unit for pot. diff. (V) = volts = 1Joule/coulombEx. 12V vs. 9V voltageSlide19

Electric current is from

_____

voltage

to

_____voltageVoltage difference is related to the _____________________________ Voltage difference is measured in _____ (V)_ _ _ _ __ _ _ _ _ _ _ _ _ __ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ Charge FlowCurrentLow Voltage

High Voltage

higher

lower

f

orce that causes electric charges to flow

voltsSlide20

___________

: a closed path that electric current follows

Electric circuitSlide21

Current and Flow Direction

The

_______

of the electric current is always from a

_____ voltage to a _____ voltage, but …The _______ in a _____actually flow from a _____ voltage to a _____ voltage

direction

higher

lower

electrons

circuit

lower

higherSlide22

Batteries

https://www.youtube.com/watch?v=CX84l5ZZHVg

Dry – Cell Batteries

Consist of

___________

surrounded by a material called an ___________Electrolyte enables ________ to move from one electrode to another_________________ occurs when the 2 terminals are connected in a ________.________ difference between these 2 terminals causes a current through a ____________.Example: _______________

Wet – Cell Batteries

Contains _________________ made of different

_______ or _________

compounds in an ___________The electrolyte is a

____________________Example:

__________

2 electrodes

electrolyte

charges

Chemical reaction

circuit

Voltage

Closed

ciruit

Flashlight battery

2 Connected plates

metals

metallic

electrolyte

c

onducting liquid solution

Car batterySlide23

Dry - Cell

Wet - Cell

Anode (negative)

Cathode (positive )Slide24

Resistance

___________

:

the tendency for a material to resist the flow of electrons and to convert electrical energy into other forms of

energy

Measured in ohms ( )Caused by _____________ which slows the movement of ____________________________ Resistor: ______________ _______________________ ______________________

Resistance

i

nternal friction

c

harges through conducting material

A special type of conductor used to control current.Slide25

Superconductor

Certain

metals and compounds that have

_____

resistance

when their temp. falls below a certain temp called ______ __________.zerocriticaltemperatureSlide26

Semiconductor

Semiconductors in

_________

are

________

.However, as atoms/impurities are added, or become compounds, these materials begin to be able to ___________________.pure stateinsulatorsconduct electric chargeSlide27

Schematic

Diagram or drawing used to build a

_______

.

There are two types of circuits.

________: one path for electrons, if one bulb goes out they all do_________: more than one path for electrons, if one bulb goes out the rest can still shinecircuitSeries

ParallelSlide28

Series and

P

arallel SchematicsSlide29

Schematic Symbols-

Draw symbols on the right side margin of notes Slide30

2 Schematic Symbols

Ammeter

read currents

in amps

Voltmeter reads potential difference in voltsSlide31

Series CircuitSlide32

Parallel CircuitSlide33

Open

vs Closed Circuit

______

circuit

allows electron to flow, lights on

______ circuit does not, lights offClosedOpenSlide34

Circuit Breakers and Fuses

Too many appliances on at the same time in a home cause the overall resistance of the circuit to be lowered.

Result is a circuit carrying more electrical current than is safe it is

___________

.

Fires can result when this happens._______________ act as a switch and open the circuit. overloadedCircuit breakers Slide35

Formulas

SI unit for

electric

charge

_________

is the quantity of the electricity transported in one second by the current of one ampere. Symbol: Potential difference, voltage (V)1Joule/coulomb (1J/C)Unit for Current (I) = Ampere (amp-A)Unit for Resistance (R) = Ohm Ω

Formula

: Resistance =

Volts/CurrentFormula with symbols

: Ω = V / I

Unit for Electric Power (P) =

Watts (Watts

)

---

Formula:

Power = Volts x Current

---

Formula with

symbols

:

P= V x

I

Amps vs volts:

https

://

www.youtube.com/watch?v=9iKD7vuq-rY

Coulomb

(C)Slide36