Electricity Flashcards
Like charges
Repel
Opposite charges
Attract
What does an object’s electrical charge depend upon?
The imbalance of its protons and electrons
-a material in which charges can move freely and that can carry an electric current
Ex. Metals
Conductor
-a material that does not transfer current easily
Insulator
Give four examples of insulators.
Plastics
Cardboard
Glass
Silk
How can objects be charged?
By the transfer of electrons
-the transfer of electrons by rubbing objects together
Charging by friction
Bc when electrons rub the wrong way they decide they want to unleash their wrath via electricity
How can objects be charged?
By touching them together
-charging by contact
Charges move within .
Uncharged objects
How can a charge be induced? This leaves the other side of the object with a positive charge
drawing electrons to one side
Even ___ can be polarized.
Insulators
-the force of attraction or repulsion between objects due a charge
Electric force
Give an example of electrical force.
Holds atoms together.
-depends on charge and distance
Electrical force
What is proportional to the electrical force between two objects?
The product of the charges on the objects
If the charge on one object is doubled,
Then the force between the two is doubled
-inversely proportional to the square of the distance between the two objects
Electrical force
-a region in space around a charged object that causes a stationary charged objectto experience an electric force
Electric field
-an electrical property of matter that creates electric and magnetic forces and interactions
Electric Charge
-the ability to move an electric charge from one point to another
Electrical Potential Energy
What does electric potential energy depend upon?
An electric charge’s position in the field
-between any two points, the work that must be done against electric forces to move a unit charge from one point to the other
Potential Difference
Potential difference is measured in
Volts (V)
Capital V because if you don’t give volts the respect they deserve they will electrify you and you will die
Volt=
joule per coulomb (J/c)
Because potential difference is measured in volts, it is often called
voltage
-a device that is a source of electric current because of a potential difference, or voltage, between the terminals
Cell
Most common batteries are
Electric cells
Voltages sets charges in ____.
Motion
Electrons move from the ____ terminal to the ____ terminal.
Negative
Positive
The electrons travel through an _____, a solution which conducts electricity.
Electrolyte
-the rate an electric charge moves through a conductor
Current
A battery is a direct current source becuase the charges always move
From one terminal to the other in the same direction
The direction current in a wire is _____ the direction that electrons move.
Opposite
-the current made of positive charges
Conventional current
-the opposition posed by a material or a device to the flow of current
Resistance
Resistance is caused by _____, which slows the movement of charges through a conducting material
Internal friction
R=
voltage/current
R=V/I
Resistance is measured in
Ohms
-volts per ampere
Ohms
-usually specially designed to control current
Resistor
Look at the math skills example on page 597
BC YOU HAVE TO
Conductors have ________
Low resistance
Some materials become _______ below a certain temperature.
Superconductors
At a critical temperature, conductors have
Zero resistance
Semiconductors have a resistance between
Conductors and insulators
Insulators have
High resistance
-a set of electrical components connected such that they provide one or more complete paths for the movement of charges
Electrical circuit
-complete path
Closed circuit
-not a complete path
Open circuit
-interrupt the flow of charges in a circuit
Switches
-used to represent circuits
Schematic Diagrams
See table 2 on page 548
BC you have to
-the components of a circuit that form a single path for current
Series
The current in each device of the current is the ____ in a series.
Same
The resistance may be ____ in a series
Different
Therefore the voltage may be ____ in a series.
Different
-a circuit in which all of the components are connected to each other side by side
Parallel
The voltage across each device in a parallel is the ___.
Same
The sum of the currents in all the devices equals the ______ in a parallel.
Total current
Look at a drawing of the series circuit and a parallel circuit
Plz
What are the advantages of a parallel circuit?
Multiple paths for current
In parallel circuits, if one path is broken,
The other still carries current
-the rate at which electrical energy is used
Electric Power
Power=
Current times voltage
Power equals
I times V
What is the SI unit for power?
Watts
P=
IV
Remember voltage is V=
IR
P=
I(squared)R or V(squared)/R
Look at the math skills on page 606
Come on last formula of the year! You have a chance of survival.
-an electrical device that contains a metal strip that melts when current in the circuit becomes too great
Fuse
-a switch that opens a circuit automatically when the current exceeds a certain value
Circuit Breaker
