Chapter 5 Flashcards
What is Electricity?
Describes all the phenomena caused by positive and negative charges
What is Electrical Charge?
A property of protons and electrons
What is the Coulomb
The unit of measurement for electrical charge. One Coulomb: 6.25x10^18 electrons or protons. Symbol=C
Explain how protons act
cannot move, they are trapped inside of the nucleus
Explain how electrons act
Can move, they rotate freely around the nucleus.
What is only transferred?
Electrons
Explain what charged objects are
all objects have the same number of positive and negative charges
What are neutral objects
same number of positive and negative charges
what are positively charged objects
more positive charges than negative
What are negatively charged objects
more negative charges than positive charges.
Explain Electrical Forces of attraction and repulsion
- opposites attract and likes repel
- Electrical charges of like signs repel each other
- Electrical charges of opposite signs attract each other
What is the law of conservation of charge
- states that Electrical charges can be neither created nor destroyed; they can only be transferred from one body to another.
what are conductors:
substance that permits the free flow of electrical charges. Ex: metals, electrolytic solutions.
What are insulators:
Substance that impedes the free flow of electrical charges. Ex: nonmetals (usually), plastic, glass, ceramics, rubber, air
What are semi-conductors:
Substance that exhibits variable conductivity, depending on different factors. Ex: metalloids, carbon, silicon.
What is static electricity:
describes the phenomena of electrical charges at rest.
What is charging by friction
- two bodies are neutral
- two objects are rubbed together, one object loses electrons
- the other gains them, both objects are charged.
What series needs to be known but not what it is ?
Triboelectric series
what is charging by conduction
- one charged object and one neutral object
- the charge of one object is shared between 2 objects when they come into contact
- two objects with like charges
What is charging by induction
- one charged objects and one neutral object
- the proximity of the charged object causes the charges in the neutral object to separate
- one charged object and one object carrying a partial positive charge on one side and a partial negative charge on the other side.
WHat is coulombs law
the force of attraction or repulsion between two charged particles determined by the amount of charge and the distance between the charges.
WHat is a magnet
an objectt that can attract other objects containing iron, cobalt, and nickel
what is ferromagnetic
magnetic objects made of iron colbalt or nickel
what is the magnetic field
the area of space in which the magnetic force of a magnet can act on another magnet. the field lines never cross
explain the magnetic forces of attraction and repulsion
opposite magnetic poles attract each other and like magnetic poles repel each other
Explain the earth’s magnetic poles
the north pole of a compass is the end that naturally seeks the earth’s magnetic south pole near the geographic north pole. SO the poles are switched on earth.
What is the electromagnetic force
this is the force generated by an electromagnetic field. Anything with an electrical current creates an EM field.
WHat is electromagnetism
describes all the phenomena resulting from the interaction between electricity and magnetism
how to make a stronger electromagnet
- more power
- more wraps
- use iron core
describes the right hand rule using the magnetic field of a live wire
- grasp the wire with the thumb pointing in the direction of the current flow (negative)
- the curled fingers point to the direction of the magnetic field
what is a solenoid
long thin loop of wire which produces a magnetic field when an electric current is passed through it
explain the right hand rule for a solenoid or electromagnet
- fingers follow current (negative)
- thumb points north
what are the factors affecting resistance
- substance: type of conductor (good or bad)
- length: the longer the wire the greater the resistance
- diameter: smaller diameter resists the flow more than a larger diameter wire
- temperature: warm wire resists more than a cold one
what is an electric current
flow of negative charges carried by electrons
what is electricity
electrical charges in motion
what is an electrical current
a network in which electrical charges can flow continuously in a loop
what is current intensity
the number of charges that flow past a given point in an electrical circuit every second
What is the unit for current intensity
I (ampere A)
how to meassure current intensity in amps
ammeter
what does the ammeter measure
the current (I in amps) flowing in through the circuit
What does the voltmeter measure
the potential difference between two points, how much the “push” has changed
what is potential difference (volts)
the amount of energy transferred between two points in an electrical circuit
what is the unit for potential difference
Volt (V)
what is the “push”
s needed to make the current flow
what is electrical resistance
the ability of a material to slow down or resist the flow of electric current
what are the units for resister
Ohm (the Lululemon sign)
what are the two types of resistor
- component that acts to reduce the current flow to lower voltage in circuits
- component that transforms electrical energy into heat, light, sound, or motion (bulb, motor, speakers)
what does the resistor act like
a dam that slows down the current
what does Ohm’s law state
staes that for a given resistance, the potential difference in a circuit is directly proportional to the current intensity
what is the triangle for volts
V
I R
what are the two types of charges called
positive and negative
what is a neutral object
has no charge/same number of psitive and negative charge
are protons available for charging objects
they cannot move and they are trapped in the nucleus therefore no they are not available for charging objects
are electrons available for for charging objects
they can move and they rotate freely around the nucleus therefore they are available for charging objects.
how do we charge an object positively
more positives than negatives
how do we charge an object negativiely
more negatives than positives
what would happen if a polyethelyne ruler was rubbed with a wool cloth
the polyethylene ruler would take the wool’s negative charges.
whar would happen if you used a cotton cloth to wipe your glass window clean
the cotton cloth would become negatively charged.
true or false: acetate rubbed with cotton will become positively charged because the acetate will gain/receive positive charges
true
true or false: polyethylene rubbed with wool will become negatively charged because the polyethylene will lose positive charges and the wool will gain/receive these positive charges
false
you have two spheres made of ebonite. you rub one with rubber and the other with cotton. what would happen if you brought both spheres together
they will attract
is this a conductor, semi-conductor, or insulator?
- the porcelain that holds wires on utility poles
insulator
is this a conductor, semi-conductor, or insulator? a copper wire in an electronic circuit
conductor
is this a conductor, semi-conductor, or insulator?
a resistor in a printed circuit
semi-conductor
is this a conductor, semi-conductor, or insulator?
the filament in a light buld
semi-conductor
is this a conductor, semi-conductor, or insulator?
the rubber coating around a wire
insulator
has the object been charged by friction, conduction, or induction?
to make a ballon stick to the wall, you rub it on your head
friction
has the object been charged by friction, conduction, or induction?
a trickle of water is redirected by a charged ruler
induction
has the object been charged by friction, conduction, or induction?
clothes are full of static electricity when they come out of the dryer
frictions
has the object been charged by friction, conduction, or induction?
a teenage boy becomes electrically charged by dragging his feet
friction
has the object been charged by friction, conduction, or induction?
you put a charged object in contact with a metal-leaf electroscope
induction
has the object been charged by friction, conduction, or induction?
confetti is drawn to charged objects
conduction
what is the difference between a electromagnet and a solenoid
electromagnet has a core and it describes all the phenomena resulting from interaction between electricity from a magnet. a solenoid has a wire that produces a magnetic field when an electric current is passed through.
