Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

GCSE Physics > 2. Electricity > Flashcards

2. Electricity Flashcards

You may prefer our related Brainscape-certified flashcards:
GCSE Geography - AQA flashcards Physics 101 flashcards GCSE Religious Studies - Edexcel Route B flashcards GCSE Religious Studies - Eduqas Route A flashcards GCSE Religious Studies - Edexcel Route A flashcards GCSE Religious Studies - Eduqas Route B flashcards AP® Physics flashcards
1
Q

what are the 3 wire ( and there colours) in a plug

A

live - brown
neutral- blue
earth- green/yellow

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

which wires are usually needed

A

live & neutral

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

if something goes wrong which wire is used to stop you from getting hurt

A

earth wire

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what does the live wire do

A

alternates between a high +ve and -ve voltage of about 230 volts

= ac (alternating current - constantly changing direction)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what voltage is the neutral wire always at

A

0 volts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

how does electricity flow through the live and neutral wire

A

flows in through the live wire and out through the neutral wire

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what are an earth wire and fuse ( or circuit breaker) used for

A

are just for safety

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

definition of earthing

A

case must be attached to an earth wire

earthed conductor can never become live

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what kind of appliances must be earthed and why

A

all appliances with metal cases

redudces the danger of electric shock

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

definition of double insulated

A

appliance with plastic casing and no metal parts showing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what is plastic

A

an insulator

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

definition of insulator

A

don’t conduct charge very well

stops a current flowing = can’t get a shock

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what does anything with double insulation not need

A

earth wire

only needs live and neutral earth wire

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what does earthing and fuses prevent

A

fires and shocks

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

how does earthing and fuses prevent fires and shocks

A
  1. fault develops (live wire touches metal case)
  2. case is earthed= big current surges to earth
  3. this surge draws a large current through the live wire
  4. current melts (blows) fuse in live wire= cuts off live supply
  5. this isolates the appliance from the live= ipossible to get electric shock
  6. also prevents risk of large fire caused by heating effect of large current
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

definition of circuit breaker

A

like fuses they protect the circuit from damage if to much current flows

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

how does a circuit breaker work

A
  1. detect a surge in current in a circuit

2. break circuit by opening a switch

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

how can a circuit breaker be more convenient than fuses

A

a circuit breaker ( and the circuit they are in ) can easily be reset by flicking a switch on the device

whereas fuses have to be replaced once they have melted

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

definition of surge

A

sudden and great incease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what does a current in a resistor result in

A

the electrical transfer of energy and an increase in temperature

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

why does an electric current in a resistor cause energy transfer which heats the resistor

A
  1. electrons collide with the ions in the lattice which make up the resistor as the flow through it
  2. this gives ions energy = causes them to vibrate and heat up
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what does the heating effect of a resistor do

A

increase the resistors resistance = less current will flow or greater voltage will be needed to produce the same current

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

how does the heating effect of a resistor work in a toaster

A
  1. toaster contain a coil of wire with really high resistance
  2. when current passes through coil = temp. increases
  3. temp increase= glows + give off infrared heat radiation = cooks bread
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

equation for power

A

power = current x voltage

P = I x V

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

equation for energy transferred ( 1st one )

A

energy transferred = current x voltage x time

E = I x V x t

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

how many volts is UK main electricity

A

230 volts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

definition a.c. supply

A

alternating current

current is constantly changing direction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

example of a.c. supply

A

mains electricity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

definition of d.c. supply

A

direct current

current keeps flowing in same direction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

example of d.c. supply

A

cells and batteries

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

explain a series circuit

A

different components are connected in a line, end to end, between +ve and -ve power supply

(except for voltmeters which are always connected in parallel , but don’t count as part of circuit )

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

what is special about a voltmeter ( in terms of circuits)

A

always connected in parallel

don’t count as part of a series circuit

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

why are series circuits not very handy

A

if you remove or disconnect one component = broken circuit = everything stops working

in practice very few thing connected in series

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

an example of something in a series circuit

A

fairy lights

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

explain a parallel circuit

A

each component is separately connected to the +ve and -ve of the supply

(except ammeters, which are always connected in series)

36
Q

what is special about ammeters ( in terms of circuits)

A

always connected in series

37
Q

what is good about parallel circuits

A

if you remove or disconnect 1 component it will hardly affect the others

38
Q

examples of things in parallel circuits

A

cars and household electrics

39
Q

how does a parallel circuit work for household electrics

A

each light switch in a house is part of a branch of a parallel circuit= just turns 1 light off on and off ( not all of them)

40
Q

what does a current in series circuit depend on

A

applied voltage ( potential difference) and the nature of other components

41
Q

when is there a bigger supply of potential difference in a series circuit

A

when more cells are in series ( all connected in same way)

eg. when 2 batteries with a potential difference on 1.5V are connected in series they supply 3V between them

42
Q

what is the case for current in a series circuit

A

it is the same everywhere

43
Q

what does the size of a current depend on

A

total potential difference (voltage ) and total resistance

I = V (total) / R (total)

44
Q

what is the case for potential difference (p.d / voltage )in a series circuit

A

the total p.d is shared between components

the p.d for each component depends on its resistance

45
Q

what is the case for total resistance in a series circuit

A

Total resistance = sum of the resistance of each component in the circuit ( R total = R 1 +R 2…)

depends on no. of components and type of components used

46
Q

what is the case for p.d in a parallel circuit

A

p. d is the same across all branches

eg. V 1 = V 2

47
Q

what is the case for current in a parallel circuit

A

current is shared across the branches

eg. I (total) = I 1 + I 2

48
Q

sketch typical current-voltage graphs for:

a. ) a wire ( at constant temp.)
b. a resistor ( at constant temp.)
c. ) a filament lamp
d. ) a diode

A

CGP pg.17

49
Q

in a parallel circuit what does the current through a branch depend on

A

the resistance of the branch

50
Q

in a parallel circuit the higher the resistance…. ( how does it effect the current )

A

higher resistance= harder it is for charge to flow= lower current ( in that branch)

if 2 identical components are connected in parallel = same current flows through each component

51
Q

name 2 components which can change resistance

A

LDRs- light dependent resistor

thermistor - temp. dependent resistor

52
Q

describe how an LDR works

be able to sketch graph

A

bright light = resistance falls

darkness = resistance is highest

53
Q

example of something that uses LDRs

A

useful device for various electronic circuits eg. burglar detectors

54
Q

describe how a thermistor works

be able to sketch graph

A

hot conditions= resistance drops

cold conditions = resistance goes up

55
Q

example of something that uses thermistors

A

make useful temperature detectors
eg. car engine temp. sensors
thermostats
fire alarms

56
Q

definition of LEDs

A

light emitting diode

emits light when a current flows through it in the forward direction

57
Q

examples of what LEDs are used for

A

digital clocks
traffic lights
remote controls

58
Q

what is the advantage of LEDs compared to a light bulb

A

they don’t have a filament which can burn out

59
Q

what are LEDs and lamps used to indicate in a circuit

A

indicate the presence of a current in a circuit

often used in appliances to show that they are switched on

60
Q

what is the equation for voltage

A

voltage = current x resistance

V= I x R

61
Q

definition of current

A

rate of flow of electrical charge

62
Q

equation for charge

A

charge = current x time

Q = I x t

63
Q

explain electric current in solid metallic conditions

A

flow of negatively charged electrons

64
Q

what is a junction in a parallel circuit

A

where current is conserved

current either splits of re-joins

65
Q

why is current conserved at a junction

A

charge cant disappear or appear — total current going into junction = total current leaving it

66
Q

voltage across 2 components connected in parallel =?

A

the same

67
Q

need to be able to calculate the currents, voltages and resistances of 2 resistive components connected in a series circuit

A

???
current = same
voltage = add
resistance = add

68
Q

definition of voltage

A

energy transferred per unit charge passed

69
Q

definition of volt

A

1 volt is 1 joule per coulomb

voltage = energy transferred / charge

70
Q

equation for energy transferred

A

energy transferred = charge x voltage

E = Q x V

71
Q

PAPER 2

definition of electrical conductors + example

A

materials that conduct charge easily - a current can flow through them

eg. metals - copper + silver

72
Q

PAPER 2

definition of electrical insulators + example

A

materials that don’t conduct charge very well - so current cant flow

eg. plastic + rubber

73
Q

PAPER 2

how are +ve and -ve electrostatic charges produced

A

by the movement of electrons

74
Q

PAPER 2

how is a +ve electrostatic charge produced

A

loss of electrons

75
Q

PAPER 2

how is -ve electrostatic charge produced

A

gain of electrons

76
Q

PAPER 2

when do forces of attraction occur

A

between unlike charges

77
Q

PAPER 2

when do forces or repulsion take place

A

between like charges

78
Q

PAPER 2

how do you create (build ) a static charge

A

take 2 insulators and rub the vigorously together

doesn’t work with conductors

79
Q

PAPER 2

what is the result of rubbing 2 insulators together

A

static charge

electrons scarped of one + dumped onto the other = +ve electrostatic charge on one + -ve on the other

80
Q

PAPER 2

explain electrostatic phenomena

A

???PAPER 2

81
Q

PAPER 2

what are the potential dangers of electrostatic charges

A

FRICTION TRANFERS ELECTRONS

eg. petrol pump= flowing petrol has friction = tranfers electrons= build static charge= spark = explosion

82
Q

PAPER 2

how do you solve the dangers of electrostatic charges ( petrol pumps )

A
  1. make pump out of metal
  2. connected to earth

= electrons will conduct to earth as the charge transfer = larges cannot build

83
Q

PAPER 2

what are the uses of electrostatic charges

A
  1. photocopiers

2. ink jet printers PAPER 2

84
Q

PAPER 2

how does electrostatic charge work in an inkjet printer

A
  1. tiny droplets forced out fine nozzle = electrically charged
  2. droplets deflected as pass between 2 metal plates
  3. voltage applied to plate- one = -ve, the other +ve
  4. droplets attracted to the plate of the opposite charge and repelled from the plate with the same charge
  5. size + direction of voltage across each plate changes = each droplet deflected to hit a different place on the paper
  6. loads of tiny dots make up printout
85
Q

PAPER 2

how does electrostatic charge work in a photocopier

A
  1. image plate = +ve charged
  2. image of what copying projected onto it
  3. whiter bits of what copying make light fall on plate = charge leaks away in those places
  4. charged bits attract -ve charge black powder =transferred on to +ve charge paper
  5. paper heated = powder sticks

6= photocopy of piece of paper

GCSE Physics (8 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions