Current Electricity and Circuits

conventional current

the flow of positive charges (protons)

• Positive charges flow from high to low potential

electric current

the flow of negative charges (electrons)

• Negative charges flow from low to high potential

battery

an object in which series of chemical reactions occur in which electrons are transferred from one terminal to another.

between these poles there is potential diffrence

voltage

a electrical pressure that pushes and pulls charges

voltage difference

the push/pull that causes charges to move (two points)

A source of energy, a closed path, a device that uses the energy

electrical circuits parts

resistance

the ability of a material to resist the flow of charge

resistor

a circut device that is designed specifically to limit current flow

what affects resistance

length, cross-sectional area, materal and temperature

Kilowatt-Hour (kWh)

the amount of energy consumed in 1 hour at a rate of 1 kW

watt

J/S

conservation on charges

electric charges cannot be created or destroyed; it can only move from one place to another. The total amount of charge in a closed system always stays the same

wire

the medium through which charges flow

current

flow rate
measured in Amperes
amound of slowing water

electromotive force (EMF)

the maximum potential difference a power source can have is called?

It is the same everywhere

How is current distributed in a series circuit?

It increases

What happens to total resistance when more resistors are added in series?

it decreases

How does increasing resistance affect current in a series circuit?

They get dimmer

What happens to light bulbs if current decreases in a series circuit?

It decreases

What happens to circuit current when more resistors are added in series?

The largest resistor

Which resistor uses the most voltage in a series circuit?

The largest resistor

Which resistor uses the most power in a series circuit?

Yes, all of them

Do all resistors in a series affect the total current?

The same as the source voltage

What is the voltage across each resistor in a parallel circuit?

It is smaller

How does the total resistance compare to the smallest resistor in a parallel circuit?

It decreases

What happens to the total resistance when more resistors are added in parallel?

Only the resistance of that branch

What affects the current in each branch of a parallel circuit?

The one with the smallest resistance

Which resistor uses the most power in a parallel circuit?

It increases

What happens to total current when more resistors are added in parallel?

electrons

electric currents transfer ____ from one place to another

lower; higher

electrons flow from a _____ potential to a ______ potential

batteries

____ and generators are devices that plump electrons to an object with a higher concentration of electrons than the original object

electrical

electron pumps convert various forms of energy to ____ energy

amperes

electric currents are measured in _____

ampere

a current flow of one coulomb per second is one _____

Ohm

____ discovered that the ratio of potential difference between the ends of a wire and the current flowing through the wire is a constant

directly

the current that flows through a wire varies ____ as the applied voltage

resistance

the ohm is a unit of electric _____

parallel

a voltmeter should be connected in ____ with the resistance in a circuit

ammeter

a(n) _____ measures the current flowing in a circuit

voltage

electric power is found by multiplying ____ by current

current

the power used by a resistor is directly proportional to its resistance and to the square of the _____ throught the resistor

temperature

in many material, resistance increases when _____ rises

power

the kilowatt hour is a unit for measuring _____

current

the thermal energy produced in a circuit from electric energy varies directly with the resistance, the time interval, and the sqaure of the _____

watts

the product of volt times amperes equals

increase resistance

which change in a circuit would reduce the current flow

sum

In a series circuit, the voltage drop across the entire circuit is equal to the_____ of the voltage drops across the individual resistors.

branches

Total current in a parallel circuit is the sum of the currents in the __________.

series

The total resistance of a(n) __________ circuit is the sum of the individual resistances.

parallel

The voltage across the branches of a(n) __________ circuit is the same everywhere.

parallel

In a(n) __________ circuit, the total resistance is less than any single resistance.

series

The current in a(n) __________ circuit is the same everywhere.

Ohm’s

A(n) __________ law may be applied to an entire circuit or to any part of the circuit.

parallel

In a(n) __________ circuit, each resistor can be operated independently.

series

It is not practical for home circuits to be wired in _________

overloads

A parallel circuit _____ when to many appliances are placed across the circuits

short circuit

A(n) _____ circuit occurs when a piece of low-resistance wire is placed across a circuit.

fuse

A(n) _______ is a short piece of metal that melts if a predetermined current in the line is exceeded.

circuit breaker

A(n) __________ is an automatic switch that cuts off the current if the circuit is overloaded.

voltmeter

A(n) __________ must be built with a very high resistance or it changes the circuit that it is designed to measure.

ammeter

The resistance of a(n) __________ should be very low so that it does not affect the circuit in which it operates.