Chapter 11 Flashcards
static electricity
1
Q
What are protons?
A
positive charge and are located in the nucleus
2
Q
what are neutrons?
A
a neutral charge and are located in the nucleus
3
Q
what are electrons?
A
a negative charge and are located around the nucleus
4
Q
what is electrical charge?
A
when an atom has an inbalance electrons and protons
5
Q
how many electrons and neutrons are there in a POSITIVELY CHARGED object?
A
have FEWER ELECTRONS than protons
6
Q
how many electrons and neutrons are there in a NEGATIVELY CHARGED object?
A
have MORE ELECTRONS than protons
7
Q
how many electrons and neutrons are there in a NEUTRALLY CHARGED object?
A
have an EQUAL NUMBER of protons and electrons
8
Q
What is static electricity?
A
Static electricity is an imbalance of electric charge on the surface of an object
9
Q
when does static electricity accumulate?
A
Accumulates on an object to form an ELECTRICAL CHARGE
10
Q
Is static electricity moving or not moving?
A
static electricity is STATIONARY
11
Q
Does static electricity move through wires?
A
NO, static electricty DOES NOT move through wires
12
Q
What are some examples of static electricity?
A
During thunderstorms - lighting
when emptying out the dryer - static cling
13
Q
When different materials are rubbed together or bump into each other a lot, ___________ leave one surface and collect on the other
+ example
A
ELECTRONS
ex. Socks rubbing against a carpet
14
Q
Some materials —– electrons and end up with a NEGATIVE charge
A
GAIN
15
Q
Some materials —- electrons and end up with a POSITIVE charge
A
LOSE
16
Q
What is a electroscope?
A
a piece of equipment used to detect electrical charges
17
Q
What are the two different types of electroscopes?
A
Pith‐Ball Electroscope
Metal Leaf Electroscope
18
Q
what does a Metal Leaf Electroscope detect?
A
used to detect electrical charge
19
Q
how does a Pith‐Ball Electroscope work?
A
Pith (plant material) is suspended by a thread, bring a charged object near the pith which is neutral. If the object is charged, the pith will be attracted to it
20
Q
What is the 3 laws of electrical charge?
A
Like charges repel
Opposite charges attract
A neutral object attracts both positively and negatively charged objects
21
Q
are most objects are neutral (uncharged) because they have the same number of positive and negative charges?
A
true!
22
Q
what two factors affect the force between charged objects?
A
- Distance
closer = stronger force
far = weaker force
- Amount of charge on each object
smaller charge = weaker force
larger charge = stronger force
23
Q
What are three methods of charging?
A
- by friction
- by conduction
- by induction
24
Q
what happenes when two neutral objects are brought together?
A
there is NO ATTRACTION
25
what happenes when a charged object is brought close to a neutral object?
it induces or causes the electrons to shift
26
what is an Induced charge separation?
is a shift in the position of electrons in a neutral object that occurs when a charged object is brought near it
27
what charge will the object be after an induced charge seperation?
Neutral charge
Although there is a shift in the positions of the electrons in the neutral object, it is still neutral – it did not gain or lose electrons.
28
Is an induced charge seperation permanent or temporary?
temporary
29
What happens when the object is moved away from the neutral object?
the electrons will return to their normal positions
30
what happenes when negative charged object is BROUGHT NEAR a metal leaf electroscope?
electrons transfer into the leaves, causing them to repel & spread apart
31
What happenes when the negative charged object is REMOVED from the metal leaf electroscope?
the metal leaf electroscope is brought back to normal
32
how do electrostatic paint sprayers work?
- paint is given a charge as it leaves the paint nozzle
- object is given the opposing charge
- charged paint particles will be attracted to the object
33
What are two common methods of charging by contact?
charging by FRICTION
charging by CONDUCTION
34
Does charging by Induction involve the objects touching each other?
NO! Charging by Induction DOES NOT involve the objects touching each other.
35
What is charging objects by friction?
transfer of electrons between two neutral objects (made from different materials)
that occurs when they are rubbed together or come in contact (touch)
36
In friction which charges would each object have?
One material is more likely to attract extra electrons (become negatively charged)
while the other material is more likely to give up electrons (become positively charged)
37
How could we know which materials will give away electrons more easily?
using the electrostatic series (also called the triboelectric series)
38
what is the electrostatic series?
a list of materials arranged in order of their tendency to gain electrons
It is a list of the ABILITY of substances to hold on to their ELECTRONS
USED FOR FRICTION
39
how can the electrostatic series be determined?
can be used to determine which substances will get a NEGATIVE CHARGE and which will get a POSITIVE CHARGE
40
What charge will the substance be if
ELECTRONS ARE LOST
(electrostatic series)
If electrons are lost → positive charge
41
What charge will the substance be if
ELECTRONS ARE GAINED
(electrostatic series)
If electrons are gained → negative charge
42
When rubbed together, the substance that is closer to the bottom of the electrostatic series will become ----, the one closer to the top will become ------
closer to the bottom becomes - negative
closer to the top becomes - postive
43
how does conduction work?
Electrons can be passed on between two objects with different amount of electric charge if they touch each other (not rubbed, just touched)
44
What happenes to an uncharged (neutral) object during conduction?
Uncharged (neutral) objects can become charged if they come into contact with charged objects.
45
What happenes when an uncharged object is charged with a neutral one during CONDUCTION?
When an uncharged object is charged with a neutral one, it will take on the same charge as the one that touches it.
46
What happens if a negatively charged ebonite rod touched a neutral pith ball during CONDUCTION?
If a negatively charged ebonite rod touches a neutral pith ball, the pith ball will also become negatively charged. The two objects will now have the same charge and will repel each other.
47
What happenes when a positvely charged object touches a neutral object?
electrons move to the positively charged object
in the end BOTH end up with SAME overall charge (POSITIVE CHARGE)
48
what happenes when a negatively charged object touches a neutral object?
electrons will move to the neutral object
in the end BOTH end up with SAME overall charge (NEGATIVE CHARGE)
49
Can only electrons move?
Yes!! only electrons can move as protons are trapped in the nucleus, so they cannot move
50
What is grounding?
directing the electricity into the ground with a conductor,
can be a way to protect ourselves against an electric shock
51
Do people who work around of alot of electric charge wear grounding straps?
yes!! Some people who work around a lot of electric charge wear grounding straps to protect themselves against an electric shock
52
What happenes to a negatively charged object in grounding?
electrons will MOVE TO the ground until object becomes neutral
53
what happenes to a postively charged object in grounding?
electrons will MOVE FROM the ground until the object becomes neutral
54
Whats an example of an Electrostatic dusters?
How does it work?
Swiffer Duster
- Uses electrostatic charges to attract dust
- When a duster is swept across an object, it causes a buildup of charge on the duster
- The neutral dust is attracted to the duster and jumps from the dusty surface to the duster
55
What is an example Electrostatic precipitators?
air purifiers & smoke stacjs
Device that uses electrostatic charge to remove soot and dust particles from the air
When smoke passes through the negatively charged plates,the particles of smoke become negatively charged through conduction
These particles than pass through a second plate which is positively charged. They are attracted to the +ve charge (since they are -vely charged)
56
What is a conductor?
- materials that allow electrons to move freely through them
57
What are some examples of good conductors?
metals - copper wires, silver, gold, steel, sea water
58
what is a insulator?
- materials that do not allow electrons to move freely through them
- Static charge remains in place in an insulator
- They can be used to protect us from electric shocks (eg. wires are often covered in plastic)
59
what are some good examples of insulators?
rubber, glass, oil, diamond, dry wood
60
what everyday items rely on both properties of conductors and insulators?
a laser printer uses BOTH insulators & conductors
61
when objects can be charged by _______ when they come into contact with another object
objects can be charged by conduction when they come into contact with another object
62
Can we charge an object without contact?
Yes!
Charging by INDUCTION: charging a neutral object by bringing another charged object close to, but not touching, the neutral object.
63
Objects can be temporarily or permanently charged by ________
Induction
64
What happenes when a charged object is brought near a neutral object during temporary induction?
when a charged object is brought NEAR a neutral object, it causes electrons to shift in position= uneven distribution of charges.
Once the charged object is moved away, the electrons will move back to their original positions
65
What is an example of temporary induction?
Ex. when a negatively charged ebonite rod is brought near but not touching a neutral pith ball, the electrons in the pith ball are repelled by the electrons in the rod. So the side of the pith ball closest to the rod becomes temporarily positively charged while the far side becomes temporarily negatively charged.
Build up of dust on a computer screen is an example of temporary induction
66
How can an object be permanently charged by induction?
An object can be permanently charged by induction by GROUNDING THE OBJECT
67
what is an example of temporary
Ex. when a negatively charged ebonite rod is brought near but not touching a neutral pith ball, the electrons in the pith ball are repelled by the electrons in the rod. So the side of the pith ball closest to the rod becomes temporarily positively charged while the far side becomes temporarily negatively charged.
If you ground the negatively charged side with your hand, some electrons will move from the pith ball to your hand which leaves the pith ball with a positive charge.
68
Charging by induction (permanently) always results in ...
Charging by induction (permanently) always results in two objects with opposite charges
69
When charging induction permanently
The object that caused the charge....
and the object that was induced will receive....
The object that caused the charge, keeps its original charge
The object that was induced will receive the opposite charge
70
what are some Technological applications of charging by induction?
Electrostatic lifting apparatus (used to make copies of footprints)
Electrostatic speakers
71
What is electric discharge?
rapid transfer of electric charge from one object to another
72
How does electric discharge work?
Electrons always move from the object with the more negative charges TO the object with the less negative charge
This discharge can sometimes be seen as sparks
The greater the charge imbalance (difference in charges), the larger the discharge , (can sometimes damage electronics or burn skin)
73
what is lightning?
Lightning is a natural process where electric charges are moving through the air.
electric discharge that occurs between clouds or between clouds on the ground
74
How do we see lightning?
We see lightning as a jagged path caused by electric charges trying to find the shortest path to the ground
The charges are drawn to tall buildings because these are the shortest path to the ground
75
What are lightning rods?
- may be placed on the top of a building to provide a safe path for lightning to follow to the ground
- usually made of metal (a conductor) and is long and pointed so it will be the tallest part of the building
lightning always try to take the shortest path to the ground
so the lightning rod will be struck first.
The charge will then be channeled down into the ground
76
lighting will always try to take the -------- path to the ground
shortest
77
What are 3 ways static electricity can charge by?
1. friction
2. conduction
3. induction
78
What are two different types of lightning?
- towards the ground
- from the ground
79
What do lightning rods do?
Allow lightning to be grounded
80
How does lightning work?
1. water droplets in clouds rub against each other becoming charged. Electrons move from the rising water molecules to the falling water droplets
2. This results in negatively charged water molecules collecting at the bottom of the cloud
3. excess negative charge at the bottom of the cloud repels the electrons on Earth’s surface directly below the cloud. Making electrons on Earth move away, leaving the area under the cloud positively charged
4. eventually charge imbalance between the bottom of the cloud and Earth’s surface becomes large and excess electrons rapidly transfer from the cloud (negatively charged) to the ground (positively charged)
5. this transfer of electrons superheats the air around it which causes both the flash of light and the rumbling sound of thunder
81
During lightning the cloud is commonly...
(CHARGE)
negatively charged
82
During lightning the groud is commonly....
(CHARGE)
positively charged
