P3 Flashcards
(150 cards)
1
Q
What happens when certain insulating materials are rubbed against each other?
A
They become electrically charged.
2
Q
What is the process of charging by friction?
A
It is when insulating materials are rubbed together, resulting in one becoming positive and the other negative.
3
Q
What happens to the charges on the insulators after they are charged?
A
The charges remain on the insulators and cannot immediately flow away.
4
Q
Can you give an example of charging by friction?
A
A plastic or polythene rod can be charged by rubbing it with a cloth.
Both the rod and cloth are insulating materials.
5
Q
What is the initial electrical state of all objects?
A
All objects are initially electrically neutral, meaning the negative (electrons) and positive charges are evenly distributed.
6
Q
What happens when electrons are transferred through friction?
A
One object becomes negatively charged and the other positively charged.
7
Q
Which object becomes negatively charged when electrons are transferred?
A
The object to which the electrons are transferred becomes negatively charged.
8
Q
Which object becomes positively charged when electrons leave?
A
The object from which the electrons leave becomes positively charged.
9
Q
What does the difference in charges lead to?
A
It leads to a force of attraction between itself and other objects which are also electrically neutral.
10
Q
How do charged objects attract neutral objects?
A
They attract the opposite charge to the surface of the objects they are attracted to.
11
Q
What happens when a cloth and rod are rubbed together?
A
Electrons are transferred to the cloth and leave from the rod.
12
Q
What are the possible charges of a particle?
A
The charge of a particle is either positive, negative, or neutral.
13
Q
What type of charge do electrons have?
A
Electrons are negatively charged particles.
14
Q
What type of charge do protons have?
A
Protons are positively charged particles.
15
Q
What type of charge do neutrons have?
A
Neutrons are neutral and have no charge.
16
Q
In a neutral atom, how do the number of electrons compare to protons?
A
In a neutral atom, the number of electrons is equal to the number of protons.
17
Q
Why do the charges in a neutral atom cancel out?
A
The equal (but opposite) charges cancel out to make the overall charge of the atom zero.
18
Q
What symbol represents a proton?
A
The symbol for a proton is +.
19
Q
What symbol represents a neutron?
A
The symbol for a neutron is O.
20
Q
What symbol represents an electron?
A
The symbol for an electron is -.
21
Q
What balances the number of positive protons in an atom?
A
The number of negative electrons in an atom balances the number of positive protons.
22
Q
What happens to an object when it gains electrons?
A
An object becomes negatively charged when it gains electrons.
23
Q
What happens to an object when it loses electrons?
A
An object becomes positively charged when it loses electrons.
24
Q
What do two charged particles or objects exert on each other when close together?
A
They exert a force on each other.
25
What are the two types of forces that charged objects can exert?
The forces can be attractive or repulsive.
26
What does an attractive force do?
An attractive force causes the objects to get closer together.
27
What does a repulsive force do?
A repulsive force causes the objects to move further apart.
28
What determines whether two objects attract or repel?
Whether two objects attract or repel depends on their charge.
29
What happens if the charges of two objects are opposite?
If the charges are opposite, they will attract.
30
What happens if the charges of two objects are the same?
If the charges are the same, they will repel.
31
What happens between opposite charges?
Opposite charges attract.
32
What happens between like charges?
Like charges repel.
33
What is the summary of attraction or repulsion for two positive charges?
Repel.
34
What is the summary of attraction or repulsion for a positive and a negative charge?
Attract.
35
What is the summary of attraction or repulsion for two negative charges?
Repel.
36
What is the summary of attraction or repulsion for a negative and a positive charge?
Attract.
37
What type of force is attraction and repulsion between charged objects?
It is a non-contact force.
38
What does a non-contact force do?
Acts on an object without being physically in contact with it.
39
What is a force that acts on an object without physical contact?
It is known as a non-contact force.
40
What is a common misconception about positively charged materials?
Materials only become positively charged because of the loss of electrons, not the gain of positive charge.
41
What are some common electrostatic phenomena?
Shocks from everyday objects, lightning, a charged balloon sticking to a wall, and a charged comb picking up small pieces of paper.
42
What saying helps remember the nature of electric charges?
"Opposites attract."
43
44
What can the build-up of electrostatic charge cause?
Sparking (electric shock)
## Footnote
This can occur when two objects are charged and create a current.
45
What occurs when two objects are charged by friction?
They become oppositely charged
## Footnote
This is a fundamental principle of electrostatics.
46
What causes electrons to 'jump' between objects?
A large surplus of electrons
## Footnote
This occurs when one object has a higher negative charge than another.
47
What is a spark in electrostatics?
A small current that flows between charged objects
## Footnote
This current is caused by the movement of electrons.
48
Give an example of a situation where a static electric spark might occur.
Touching a door handle after walking on vinyl floor with rubber shoes
## Footnote
This is a common example of everyday electrostatic discharge.
49
What can sparks ignite?
Flammable gases and liquids, such as petrol
## Footnote
This makes electrostatic discharges potentially dangerous.
50
Fill in the blank: A static electric spark occurs when two objects are _______.
charged by friction
51
True or False: A current is the flow of protons.
False
## Footnote
A current refers to the flow of electrons, not protons.
52
What is the main risk associated with static electric sparks?
They can cause fires
## Footnote
This is particularly concerning in environments with flammable materials.
53
What can the build-up of electrostatic charge cause?
Sparking (electric shock)
## Footnote
This can occur when two objects are charged and create a current.
54
What occurs when two objects are charged by friction?
They become oppositely charged
## Footnote
This is a fundamental principle of electrostatics.
55
What causes electrons to 'jump' between objects?
A large surplus of electrons
## Footnote
This occurs when one object has a higher negative charge than another.
56
What is a spark in electrostatics?
A small current that flows between charged objects
## Footnote
This current is caused by the movement of electrons.
57
Give an example of a situation where a static electric spark might occur.
Touching a door handle after walking on vinyl floor with rubber shoes
## Footnote
This is a common example of everyday electrostatic discharge.
58
What can sparks ignite?
Flammable gases and liquids, such as petrol
## Footnote
This makes electrostatic discharges potentially dangerous.
59
Fill in the blank: A static electric spark occurs when two objects are _______.
charged by friction
60
True or False: A current is the flow of protons.
False
## Footnote
A current refers to the flow of electrons, not protons.
61
What is the main risk associated with static electric sparks?
They can cause fires
## Footnote
This is particularly concerning in environments with flammable materials.
62
What happens when electrons travel from the ground to a person?
Electrons jump to an uncharged person from shoes rubbing the carpet.
63
What causes sparking when touching a door handle or another person?
Electrons transfer from one object to another, resulting in a spark.
## Footnote
Example: Sparking from touching a door handle or another person.
64
How do clouds become charged during a storm?
Clouds move over each other, causing electrons to be transferred between them.
65
What happens when negative charges from clouds meet positive charges on the ground?
They create a giant spark, which is a current from a transfer of charge.
66
What happens when negative charges from the cloud meet positive charges on the ground?
They create a giant spark, which is a current from a transfer of charge.
## Footnote
This phenomenon is known as lightning.
67
What is lightning?
Lightning is the phenomenon that occurs when negative charges built up on the cloud are attracted to positive charges on the ground.
68
What happens when negative charges from the cloud meet positive charges on the ground?
They create a giant spark, which is a current from a transfer of charge.
## Footnote
This phenomenon is known as lightning.
69
What is lightning?
Lightning is the phenomenon that occurs when negative charges built up on the cloud are attracted to positive charges on the ground.
70
What causes lightning?
Lightning is caused by the build-up of charge in clouds.
71
What happens when a balloon is rubbed on a woollen jumper?
Rubbing a balloon on a woollen jumper transfers electrons onto the balloon by friction, making the balloon negatively charged and the jumper positively charged.
72
Why does a balloon stick to a wall?
The balloon sticks to the wall due to electrostatic attraction, as the positive charges in the wall are attracted to the negative charge of the balloon.
73
What occurs when a plastic comb is run through hair?
Running a plastic comb through hair transfers electrons to the comb, giving it a negative charge.
74
What happens to hair strands after using a charged comb?
The hair strands become positively charged and begin to repel each other.
75
How do pieces of paper react to a charged comb?
Pieces of paper jump up and stick to the comb due to static electricity, as the positive charges in the paper are attracted to the negative charges on the comb.
76
What is the reason papers stick to the comb?
The papers stick to the comb through static electricity.
77
How does a comb become charged?
The comb becomes charged by friction from the hair, resulting in a negative charge as electrons are transferred to it.
78
What happens to the hair strands when the comb becomes negatively charged?
The hair strands become positively charged and begin to repel each other.
79
What occurs when a charged comb comes close to neutral pieces of paper?
The positive charges in the paper are brought to the surface and attracted to the negative charges on the comb.
80
What is the result of the attraction between the comb and the paper?
The papers 'stick' to the comb through static electricity.
81
What can a negatively charged comb attract?
A negatively charged comb can attract small pieces of paper.
82
What creates an electric field?
A charged object creates an electric field around itself.
83
How is an electric field similar to a magnetic field?
An electric field is similar to the way in which magnets create magnetic fields.
84
How can an electric field be defined?
An electric field is a region where an electric charge experiences a force.
85
What happens when other charges enter an electric field?
They will experience an electric force, attracting or repelling them from the object.
86
What determines the direction of the electric force?
The direction of the force depends on whether the charges are the same or opposite.
87
What type of force occurs between like charges?
The force is repulsive between like charges.
88
What happens to like charges in an electric field?
Like charges (negative and negative or positive and positive) will move away from each other.
89
What type of force occurs between opposite charges?
The force is attractive between opposite charges.
90
What happens to opposite charges in an electric field?
Opposite charges (negative and positive) will move toward each other.
91
What happens when the negative particle enters the electric field?
It feels a force of attraction towards the positive charge.
92
What does the size of the force depend on?
The strength of the electric field at that point.
93
How does the force change as the distance between charged objects decreases?
The force becomes stronger.
94
How does the force change as the distance between charged objects increases?
The force becomes weaker.
95
How can electric fields be represented?
Electric fields can be shown by electric field lines.
96
What direction do electric field lines point relative to charges?
Field lines always point away from positive charges and towards negative charges.
97
What shape do electric field lines around point charges take?
Electric field lines around point charges are spherical.
98
How are field lines drawn in relation to the charge?
Field lines are drawn perpendicular to the charge.
99
What direction do field lines take for a positive point charge?
Field lines are directed away from a positive charge.
100
What direction do field lines take for a negative point charge?
Field lines are directed towards a negative charge.
101
What happens when two opposite charged point charges are brought close together?
Their attraction is shown by the field lines.
102
What type of electric field is present between two parallel plates?
A uniform electric field
## Footnote
This means that the strength and direction of the electric field are constant throughout the space between the plates.
103
In a uniform electric field between two parallel plates, the field lines are directed from _______ to _______.
[positive plate] to [negative plate]
## Footnote
This indicates the direction of the force that a positive charge would experience in the field.
104
Describe the characteristics of the field lines in a uniform electric field between two parallel plates.
The field lines are:
* Directed from the positive to negative plate
* Parallel
* Straight lines
## Footnote
These characteristics reflect the nature of the electric field between the plates.
105
What determines the strength of an electric field?
The strength of an electric field is determined by the spacing (the concentration) of the field lines.
106
What does a stronger electric field look like?
A stronger field is represented by the field lines closer together.
107
What does a weaker electric field look like?
A weaker field is represented by the field lines further apart.
108
In which direction are electric field lines directed between two parallel plates?
Field lines are directed from the positive to the negative plate.
109
What is the characteristic of the electric field strength in a uniform electric field?
The electric field strength is equal at all points in this field.
110
How is the electric field strength represented in a non-uniform electric field?
The electric field strength is stronger where the lines are closer together.
111
What is the difference between uniform and non-uniform electric fields?
A uniform electric field has evenly spaced field lines, while a non-uniform electric field does not.
112
What is electric current?
Electric current is defined as the rate of flow of charge.
113
How is the size of an electric current measured?
The size of an electric current is the amount of charge passing through a component per second.
114
Why are wires in an electric circuit made of metal?
Wires in an electric circuit are made of metal because metal is a good conductor of electric current.
115
What does the current in the wires represent?
In the wires, the current is a flow of electrons.
116
What is the relationship between electrons and metal ions?
Electrons flow in metal, where they can be represented as: ELECTRONS + = METAL ION, 0 = ELECTRON.
117
How is the amount of current flowing through a component measured?
The amount of current flowing through a component is measured using an ammeter.
118
How should ammeters be connected in a circuit?
Ammeters should always be connected in series with the part of the circuit you wish to measure the current through.
119
What is the equation for calculating electric current?
Current = charge / time
## Footnote
Where: I = current (A), Q = charge (C), t = time (s)
120
What does 'I' represent in the current equation?
'I' represents current, measured in amperes (or amps, A).
121
What does 'Q' represent in the current equation?
'Q' represents charge, measured in coulombs (C).
122
What does 't' represent in the current equation?
't' represents time, measured in seconds (s).
123
How can the equation for current be rearranged?
The equation can be rearranged using a formula triangle.
124
What is the conversion of 10 mA to A?
10 mA = 10 × 10^-3 A
125
What conditions must be met for current to flow in a circuit?
1. The circuit includes a source of potential difference.
2. The circuit is closed - i.e. there are no gaps in the circuit.
126
What are sources of potential difference?
1. A cell
2. Batteries (multiple cells)
3. Electrical generator
127
What is true about current in a closed-loop circuit?
In a closed-loop circuit, such as a series circuit, the current is the same value at any point.
128
Why is the current the same at any point in a closed-loop circuit?
The number of electrons per second that passes through one part of the circuit is the same number that passes through any other part.
129
What does it mean for components in a closed-loop circuit?
All components in a closed-loop have the same current.
130
How can current be converted into standard units?
10 mA = 10 × 10-3 A
131
What is required for a current to flow in a circuit?
1. A source of potential difference
2. The circuit is closed - i.e. there are no gaps in the circuit
132
What are sources of potential difference?
1. A cell
2. Batteries (multiple cells)
3. Electrical generator
133
What happens to current in a closed-loop circuit?
The current is the same value at any point.
134
Why is the current the same in a closed-loop circuit?
The number of electrons per second that passes through one part of the circuit is the same number that passes through any other part.
135
What does it mean for components in a closed-loop circuit?
All components in a closed-loop have the same current.
136
What is the current at each point in a closed-loop?
The current is the same at each point in a closed-loop.
137
What happens at a junction in a circuit?
At a junction in a circuit, the current is conserved.
138
What does it mean for current to be conserved at a junction?
The amount of current flowing into the junction is equal to the amount of current flowing out of it.
139
Why is current conserved at a junction?
This is because charge is conserved.
140
What must the current coming into a junction equal?
The current coming into a junction must equal the current coming out of a junction.
141
What is the flow of current in electrical wires?
In electrical wires, the current is a flow of electrons.
142
What charge do electrons have?
Electrons are negatively charged.
143
Where do electrons flow from in a circuit?
They flow away from the negative terminal of a cell.
144
What must the current coming into a junction equal?
The current coming into a junction must equal the current coming out of a junction.
145
What is current in electrical wires?
In electrical wires, the current is a flow of electrons.
146
What charge do electrons have?
Electrons are negatively charged.
147
Where do electrons flow?
Electrons flow away from the negative terminal of a cell towards the positive terminal.
148
How is conventional current defined?
Conventional current is defined as the flow of positive charge from the positive terminal of a cell to the negative terminal.
149
How does conventional current relate to electron flow?
Conventional current is the opposite to the direction of electron flow.
150
Why was conventional current defined in its way?
Conventional current was described before electric current was really understood.
