Physics Topic 2 Flashcards
1
Q
Switch
A
Used to turn a circuit on off
2
Q
Lamp
A
Electrical current heats the filament in a bulb so it gives out light
3
Q
Fixed resistor
A
A resistor restricts or limits the flow of electrical currents it has a resistance that doesn’t change
4
Q
Variable resistor
A
Changes the resitance
5
Q
Thermistor
A
The resistance if this depends on the temp at low temp the thermistor had a high resistance as the temp increases the resistance decreases
6
Q
Let
A
The resistance of the lot depends on light at low light levels it has a high resistance
7
Q
Diode
A
Allows current to flow in one direction
8
Q
Voltmeter
A
Something measuring the electrical potential
9
Q
Ammeter
A
Measuring electrical current
10
Q
If the current constantly changes direction its called
A
Alternating current
11
Q
If he current flow in one direction its called
A
Direct current
12
Q
Series currents are useful if
A
You want a warning that one of the components have failed
13
Q
Electricity is a useful form of
A
Energy
14
Q
Current is measures in
A
Amperes
15
Q
Electrical Potential difference also means
A
Charge
16
Q
What are the units of power
A
Watts
17
Q
Units of voltage and potential difference
A
VoLTE
18
Q
Which type of circuit is currentconserved
A
Parallel
19
Q
In a series circuit the current across each component is
A
Same
20
Q
In a parallel circuit the current is
A
Shared between each component connected in parallel
21
Q
The voltage in a parallel circuit depends on
A
The battery
22
Q
If one component breakes and all the others break too how are they connected
A
In series
23
Q
What type of current flows from batteries
A
AC
24
Q
What does aC stand for
A
Alternating current
25
DC stands for
Direct current
26
What is direct current
When the current flows in only one direction
27
Electrical current is the rate of
Electric charge
28
No current can flow if
The circuit is broken
29
An electric current flows when
Electrons move through a conducter
30
A potential difference is
The driving force that punches the charge around
31
The current flowing through a component is measure using an
Ammeter
32
The ammeter must be connected in
Series
33
The resistance in a wire increases as
The length of wire increases and thickness
34
Voltage=
Current x resistance
35
Voltage can only be measured in
Parallel
36
What causes resistance
Electrons colliding with ions in the conducter
37
What's ohms law
V =current x resistance
38
Charge flow=
Current x time
39
Copper wires are
Good conducter
40
Plastic wires
Good insulated
41
Potential difference is
A measure of how much energy is transferred between 2 points in s circuit
42
Potential difference =
Current x resistance
43
Electrical charge will only flow round a complete circuit if
There's a source of potential difference
44
The current flowing through a component depends on
The potential difference across it and the resistance
45
The greater the resistance across a component the
Smaller the current that flows
46
Total charge through a circuit depends on
Current and time
47
The size of the current is the
Rate of flow of charge
48
More charge passes Through a circuit when
A larger current flows
49
The ammeter must always be place in
Series with whatever your investigating
50
The voltmeter must be place in
Parallel
51
Ohmic conductors have a
Constant resistance
52
At a constant temp the current flowing through an ohmic conductor is
Directly proportional to the potential difference accross it
53
The resistance of some resistors for eg diode does
Change
54
What is IV characteristic
A graph which shows how the current flowing through a component changes as the potential difference across it increases
55
Fixed resistor Has an IV characteristics that's a
Straight line
56
A filament lamp or diode have ________ IV characteristics
Curved
57
Ldr is a resistor that is ________ on the _________ of ______
Dependant
Intensity
Light
58
Sensing circuits are used to
Turn on our increase the power to components depending on conditions they are in
59
Series circuits
vt=
It=
Rt=
V= v1+v2
It=I1=i2
Rt= r1+r2
60
Parallel circuits
Vt=
It=
Rt=
Vt=v1=v2
It=i1+i2
rt= r1+r2
61
What is the blue wire
Neutral
62
What is the Brown wire
Live
63
What Is the green/yellowy wire
Earth wire
64
What is the job of neutral wire
It completes the circuit and caries away current
65
Job of live wire
Provides the alternating potential difference
66
Job of earth wire
It doesn't carry current and it stood the appliance casing from becoming live
67
Mains supply is
Ac
68
Battery supply is
Dc
69
The frequency of the ac mains is
50Hz
70
Cells and batteries supply
Direct current
71
What is current
The flow of electrons
72
What is charge
Value of electricity flowing through a circuit
73
Charge is measure in
Couloumbs
74
Current is measured in
Amperes
75
Graph for resistor is
Directly proportional
76
Filament lamp graph looks like
A curve
77
Diode graphs look like
Straight at first then goes up
78
Why is thermistor used in central heating
To only let current flow in certain temp
79
In series the current is
The same
80
In parallel the current is
Split
81
I'm series the pd is
Split
82
In parallel the pd is
The same
83
In series the resistance is
All added
84
In parallel the resistance is l
Lower than the lowest resistance
85
Energy transferred=
Charge flow x pd
86
Power2=
Pd x current
87
Job of live wire
Carry the pd from the live supply
88
Job of neutral wire
Completes circuit
89
Job of earth wire
Doesn't let the appliance become live
90
Power =
V x I
91
Energy transferred=
Charge flow x pad
92
P=
I2 x R
93
National grid is a big system of
Cables
Transformers
Power stations
Consumers
94
Ng uses a
High pd low current
95
What is problem w high current on NG
Loses loads of energy wire heats up
96
NG transfers
Electrical power from power stations to anywhere on Grid
97
What is cheaper for the NG to do relating to current and volt
Boost PD and make current lower
98
Increasing the PD decreases the current which makes it more
Efficient
99
PD is changed by
Transformers
100
Step up transformer -
Steps PD at one end
101
Step down transformer-
Steps down PD to make it safe and useable for consumers
102
Energy transferred =
| Energy transferred =
Charge flow x PD
| Power x time
103
Power =
Powe=
Power=
PD x current
Current x resistance
Et divide by time
104
Build up of static is caused by
Friction
105
How is static electricity caused
When two insulating materials together
106
What happens when two materials are rubbed together r
Negatively charged electrons will be scraped of one and dumped on the other
107
+ve and -ve are produced by
Electrostatic charges
108
Electrostatic charges are produced by
Movement of electrons
109
As electric charge builds up the pd between the object and Earth ______
Increases
110
How is a spark caused
When the PD between the object and Earth increases and gets large enough electrons can jump accross the gap between the object and Earth
111
Like charges _____
| Opposite charges ______
Reppell
| Attract
112
When two electrically charged objects are bough close to each other tndh
Except a force to one another
113
Electric charges create a
Electric field
114
When a charged object is places in the electric field of another objects it feels a force which is caused by
Electric fields of each charged object interacting with each other
115
If you increase the distance between two charged objects the strength of the field _________ and the force between them become s
Decreases and the force between them becomes smaller
116
Sparks-'high PD causes a _ between the ____ and __
| The strong electric field causes the ...
Strong elctrostatic field
Charged object
Earthed objects
Electrons in air particles to be removed, ionisation,
117
Air is normally a insulator but when ionised it is
More conductive so current can flow through it which was cause a spark
118
Sparks are caused when
There is a high PD between the earth and charged object
