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All matter is composed of tiny building blocks known as

atoms

The central region of an atom that contains most of its mass is the

Nucleus

An object becomes electrically charged when it gains or loses

electrons

an atom that gains extra electrons becomes

negative ion

The Si unit to measure electric charge is the

coulomb

a material that resists the flow of electric charge is an

insulator

substances with relatively low resivivity behave as good

conductors

substances whose conductivity can change under certain conditions are called

semi conductors

charging an object by touching it with another charged object is charging by

conduction

opposite electric charges always

attract

The strength of an electric feild is measured in

newtons per colomb

Electric field lines show the direction a

positive test charge would move

If two charges move twice as far apart, the electric force

becomes one fourth as strong

a test charge used when analyzing electric fields is assumed to be

Positive

electric potential difference is commonluy meausred in

volts

resistance in a circut acts to

reduce current

a 60 watt device operating at 120 volts draws a current of

.5A

a battery increases a charges

electric potential energy

The standard unit for measuring electric current is the

amphere

Ohm's law relates voktage, current, and

resistance

three reistsors of 5, 15 and 30 omega

60 omega

In a parallel circut, adding more resitors will

decrease total resitance

two 12 omega resistors in parallel have an equivalent resitance of

6 omega

the electric feild around a 4x10^-6 charge at 1 meter is closet to

3600 N/C

In parallel circuts, the total current enetering a junction

splits among the branches

In series circuts, the current through each resistor

is the same everywhere

a 24 V battery connected to resistors of 4 omega, 8 omega, and 4 omega in series produces a current of

2A

Increasing resistance in a circut will make the current

Decrease

electric forces are stronger than gravitorial forces because

electric charges interact more strongly

two resistors of 15 omega and 30 omega are connnected in parallel. thier total resitance is

10 omega

the particle with a anegative charge is the

electron

a material that allows some but not all electrons to move is called a

semiconductor

the region around a chathe where forces are felt is called an

electric feild

the dfirection of electric field lines depends on the

sign of the test charge

doubling one charge while keeping distance the same makes the force

twice as large

voltage can also be described as

energy per charge

a 90 W appliance running on 30 V draws a current of

3 A

Increasing voltage in a circut will

increase current

the ratio of voltage to current defines

resistance

The combined resistance of 10 Omega, 10 omega, and 5 omega in series is

25 omega

in parallel circuts, the branch with the least resistance has

the greatest current

Two 8 omega resistors in parallel have a total resistance of

4 omega

The elctric field around a 1 x 10^-6 charge at .5 m is about

180000 NC

current in a series circut is determined by

the total resistance

a circut has a 60 v battery and resistors of 10 omega and 20 omega in a series. The current is

2A

a device with higher resistance will have

less current

electron force is extremley strong compared to gravity because

electric charges are much larger than masses

a parallel circut with resistors of 6 omega and 3 omega has a total resitance of

2 omega

electric charge is best described as a property that

causes electric forces

when more resistors are added in series, the total resistance.

increases