3) Electricity Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

What does a cell do?

A
  • pushes current around a circuit- the current comes out of the + and back into the -
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is a battery?

A
  • two or more cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is a lamp?

A
  • when a current flows the filament gets hot and glows
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is a switch ‘open’

A
  • ‘open’ means ‘off’
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is a switch (closed)

A
  • ‘closed’ means ‘on’
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is a fuse?

A
  • a fuse will melt if too much electricity flows
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is a voltmeter?

A
  • measures voltage in volts
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is an ammeter?

A
  • measures current, in Amps
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is a diode?

A
  • a diode only lets current flow one way
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is a resistor?

A
  • is difficult for a current to go though
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is a variable resistor?

A
  • a resistor that we can adjust
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is a thermistor?

A
  • allows current to flow when you heat it
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is an LDR (Light Dependent Resistor)?

A
  • allows current to flow when light hits it
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the symbol for a cell?

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

What is the symbol for a battery?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the symbol for a switch (open)?

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

What is the symbol for a switch (closed)?

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

What is the symbol for a fuse?

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

What is the symbol for a voltmeter?

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

What is the symbol for an ammeter?

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

What is the symbol for a diode?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is the symbol for a resistor?

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

What is the symbol for a variable resistor?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is the symbol for a thermistor?

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

What is the symbol for a LDR?

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

An electric current in solid ________ conductors is a flow of __________ charged electrons

A
  • metallic- negatively
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Define current?

A
  • current is the ‘flow’ of electricity- rate of flow of charge
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What do we measure current with?

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

How do we put an ammeter in the circuit?

A
  • in series with the thing we’re measuring- because ammeters have a very low resistance
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What is the current like in a series circuit?

A
  • the current is always the same
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What is the current like in a parallel circuit?

A
  • the current is split up in a parallel circuit
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Define voltage

A
  • the ‘push’ from the battery that makes a current flow- also called potential difference
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

How do we put a voltmeter in a circuit?

A
  • in parallel with the thing we’re measuring
34
Q

What is the voltage like in a series circuit?

A
  • not the same voltage- if you add V1 and V2 you get V3
35
Q

What is the voltage like in a parallel circuit?

A
  • voltage is always the same
36
Q

Current (I) is ________ ____________ to Voltage (V) in a __________ wire

A
  • directly proportional- resistance
37
Q

What is the relationship between the current (I) and voltage (V) in a diode?

A
  • negative bias - no current flows (resistance very high)- positive bias (0V-0.6V) no current flows (resistance is high)- positive bias - (above 0.6V) current increases quickly because resistance has decreased
38
Q

What does the I-V graph look like for a diode?

A

””

39
Q

What does the I-V graph look like for a resistance wire?

A

””

40
Q

What does the I-V graph look like for a metal filament bulb?

A

””

41
Q

Equation for the relationship between voltage, current and resistance:

A

voltage = current by resistance V =IR

42
Q

What is resistance measured in?

A
  • ohms
43
Q

What causes resistance?

A
  • as the electrons move through the conductor, come collide with atoms, other electrons, or impurities in the metal- these collisions cause resistance
44
Q

How to calculate charge?

A

charge (coulombs) = current (amps) by time (seconds) Q = It

45
Q

How do you calculate charge?

A

Q=E/V - E energy transferred (Joules) - Q = charge (coulombs) - V = potential difference (volts)

46
Q

What is voltage?

A
  • energy transferred per unit charged passed
47
Q

How to calculate voltage?

A

V=E/Q volts = joule/coulomb

48
Q

What is the symbol for resistance?

A

”- ohms “

49
Q

What is the qualilative variation of a thermistor with temperature?

A
  • As temperature increases, resistance decreases- as temperature increases, more electrons are freed up for conduction
50
Q

What is the qualilative variation of an LDR with illumination?

A
  • as light intensity increases, the resistance decreases- more electrons are freed up for conduction
51
Q

There is a ______ current through the resistor in bright light because the __________ is _____

A
  • higher- resistance- lower
52
Q

Electric current in solid metallic conductors is a flow of __________ charged _________

A
  • negatively- electrons
53
Q

What is the electricity provided for the home called?

A
  • mains supply
54
Q

Label a plug diagram:

A

””

55
Q

Why are wires made of copper?

A
  • conducts eectricity- ductile
56
Q

Why is the Earth pin longer than others?

A
  • makes contact first - so its always connected (afety)
57
Q

What are 5 electrical safety features?

A
  • insulation- double insulation- earthing- fuses- circuit breaker
58
Q

What is insulation?

A
  • when plastic is used to protct the user from getting a shock when touching the component
59
Q

What is double insulation?

A
  • when plastic is used to protct the user from getting a shock when touching the component
60
Q

Where do we find insulation?

A
  • electrical components that don’t need an earth wire
61
Q

Where do we find double insulation?

A
  • electrical components that don’t need an earth wire
62
Q

How does insulation work?

A
  • plastic is an insulator- thus the electric component does not need an earth wire to protect the user from getting a shock
63
Q

How does double insulation work?

A
  • plastic is an insulator- thus the electric component does not need an earth wire to protect the user from getting a shock
64
Q

What is the symbol for double insulation?

A
  • one smaller square inside a bigger square
65
Q

What is earthing?

A
  • this is a wire that is attached to the earth
66
Q

Where do find earthing?

A
  • found earth wire and earth pin in plugs
67
Q

How does earthing work?

A
  • with the earth wire in place, the current goes through the earth wire and not the person touching it- the pole and coil are burried 2-3 meters underground
68
Q

How do fuses work?

A
  • contains a thin wire that heats up and melts if the current is too high
69
Q

Where are fuses found?

A
  • normally found in between an electrical power source and the electrical component
70
Q

Why is it important to choose the correct fuse?

A
  • the wire needs to melt once the current is too high
71
Q

What is a circuit breaker?

A
  • automatically operated electrical switches that protect circuits from overloading or short circuiting
72
Q

Where are circuit breakers found?

A
  • found in fuse boxboards in modern houses instead of the fuses
73
Q

How does a circuit breaker work?

A
  • electromagnetic switch opens when the current is greater than a certain value- this enables the circuit to be turned off when there is a risk of danger
74
Q

Why are circuit breakers better than fuses?

A
  • more sensitive than fuses- can be reset more quickly
75
Q

How do you calculate power?

A

P=VI power = voltage by current

76
Q

What is a.c ?

A
  • alternating current - the voltage and current change directions many times each second
77
Q

What is d.c?

A
  • direct current - constant current in one direction
78
Q

What is an RCCB?

A
  • circuit breaker - the device disconnects a circuit when it detects that the current is not the same in the live and neutral wires - when the currents are different, there is a small current leaking to earth, which could be through the body of a person who accidentally touches the live wire
79
Q

How do you calculate energy transferred (E)?

A

E = VQ E = energy transferred (Joules (J)) V = potential difference (Volts (V)) Q = charge (Coulombs (C)) E = IVt E = energy transferred (Joules (J)) V = potential difference (Volts (V)) I = current (Amps (A)) t = time (seconds (s)

80
Q

What are watts?

A

joules per second (J/s)