the flow ofthe flow of charged particlescharged particles;

can be positive or negative,but usually negative (electrons)

through a conducting metal

Field lines Field lines point away from positivepoint away from positive and and toward negative chargestoward negative charges..

An electric field exists in a region in An electric field exists in a region in space if a charge placed in that region space if a charge placed in that region

experiences an electric force.experiences an electric force.

Electric FieldsElectric FieldsElectric FieldsElectric Fields

Write this down!

Quantity Symbol Units Formula

Electric Potential Difference (a.k.a. voltage)

V V

(volt)

V = W/Q

W is work

Q is charge

Current I A

(ampere)

I=Q/t

Q is charge

T is time

Resistance R Ω

(ohm)

R=V/I

V is voltage

I is current

Electric Potential Difference (a.k.a. voltage)

Electric Potential Difference (a.k.a. voltage)

the change in the change in electric potential electric potential energyenergyper unit chargeper unit charge

V = W/QThe SI unit of electric potentialdifference is the voltvolt, named inhonor of Alessandro Volta.

One One voltvoltis the is the electric potential differenceelectric potential difference

between two points when between two points when one jouleone joule of of workwork

is done in moving is done in moving one coulombone coulomb of charge of chargebetween the points.between the points.

VoltmeterVoltmetera device that measures

electric potential difference

Electric current (I) is measuredin amperes, in honor ofAndre Marie Ampere.

One ampere is the flow ofOne ampere is the flow ofone coulomb of charge per second.one coulomb of charge per second.

1 amp = 1 coulomb per second = 1 C/s1 amp = 1 coulomb per second = 1 C/s

II = QQ/tt

AmmeterAmmetera device that measures current

attached in series

ResistanceResistance

determines the amount of current flowdetermines the amount of current flow

= the ratio of potential difference to current= the ratio of potential difference to current

RR =VVII

The SI unit of resistance is the ohmohm, , namedin honor of Georg Simon Ohm.

One ohmOne ohm of resistance is the resistancesuch that one voltone volt of potential differenceis needed to obtain a current of one ampone amp.

powerpower = = workwork//timetime

= (= (workwork//chargecharge))..((chargecharge//timetime))

== electric potential differenceelectric potential difference ..

currentcurrent

PP ( (WattsWatts) = ) = VV ( (VoltsVolts))..II ( (AmpsAmps))

Ohm’s LawOhm’s LawThe ratio of potential difference to currentThe ratio of potential difference to current

is constant.is constant.

If R = V/I is a constant valueIf R = V/I is a constant valuefor a given resistor, then thatfor a given resistor, then that

resistor is said to obey Ohm’s Law.resistor is said to obey Ohm’s Law.

Kirchhoff’s RulesKirchhoff’s Rules

Loop Rule: Loop Rule: The sum of the potential differences The sum of the potential differences (voltage) around any closed circuit loop is zero.(voltage) around any closed circuit loop is zero.

Kirchhoff’s RulesKirchhoff’s Rules

Junction Rule: Junction Rule: The sum of the currentsThe sum of the currentsinto any circuit junction is zero.into any circuit junction is zero.

The site linkedThe site linkedhere allows youto build and test to build and test your own series,your own series,parallel, and/orparallel, and/orcombination circuits.combination circuits.