electricity Flashcards

1
Q

function of: cell

A

Provides electrical energy to charges in a circuit.

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2
Q

function of: battery

A

Provides electrical energy to charges in a circuit.

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3
Q

function of: diode

A

Allows current to flow through it in one direction only

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4
Q

function of: resistor

A

Used in circuits to set current.

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5
Q

function of: variable resistor

A

Used to vary the size of current in a circuit.

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6
Q

function of: fuse

A

A fuse melts to break the circuit if the current is too large.

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7
Q

function of LED:

A

convert electrical energy directly into light

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8
Q

function of: lamp

A

heats up when an electric current passes through it and produces light

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9
Q

function of: switch

A

turn electric circuits ON and OFF

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10
Q

function of: voltmeter

A

measure the voltage, or potential variation, between two locations

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11
Q

function of: ammeter

A

measure the current in a circuit

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12
Q

function of: thermistor

A

measure the temperature of a device

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13
Q

function of: LDR

A

detect light levels

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14
Q

The rate of flow of charge in a circuit =

A

Current

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15
Q

The difference in potential between two points of a circuit. Causes a current to flow =

A

Potential Difference / voltage.

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16
Q

the amount of electricity travelling through a circuit =

A

Charge

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17
Q

Anything that slows the flow of charge around a circuit.
Resistance is usually caused by electrons colliding with
ions in a material =

A

Resistance

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18
Q

A circuit with a single loop of wire =

A

Series Circuit

19
Q

A circuit with two or more loops (branches) of wire =

A

Parallel Circuit

20
Q

Describe the difference between a series circuit and a parallel circuit.

A
  • A series circuit contains only one loop of wire.
  • A parallel circuit contains two or more loops (branches) of wire.
21
Q

charge flow (c) =

A

current (A) x time (s)

22
Q

Potential Difference (V) =

A

Current (A) x Resistance (Ω)

23
Q

at a constant temperature is ….

A

directly proportional

24
Q

As the current increases, the temperature of filament increases therefore ….

A

the resistance of the filament lamp increases.

25
Q

resistance (Ω) =

A

potential difference (v) / current (A)

26
Q

Describe how the currents in a series circuit and a parallel circuit differ.

A
  • Series circuit – same current at any point of the loop.
  • Parallel circuit – the total current through the whole circuit is the sum of the currents in each loop
27
Q

What does A.C stand for?

A

Alternating current.

28
Q

What does D.C stand for?

A

Direct current.

29
Q

Describe the difference between an alternating potential difference and direct potential difference.

A
  • An alternating potential difference will go from positive to negative repeatedly.
  • Producing an alternating current in a circuit.
  • A direct potential difference will stay either positive or negative, but not change sign.
  • Producing a direct current in a circuit.
30
Q

What is the frequency and potential difference of mains electricity in the U.K?

A

Frequency 50Hz
Potential difference 230V

31
Q

Live wire (Brown) =

A

Carries alternating potential difference from the supply.

32
Q

Neutral wire (Blue) =

A

Completes the circuit.

33
Q

Earth wire (Yellow/Green) =

A

Safety wire to stop appliance becoming live

34
Q

Explain why a live wire may be dangerous even when a switch in the mains circuit is open.

A

A person could complete the circuit to ground getting electrocuted.

35
Q

Power (W) =

A

Potential Difference (V) x Current (A)

36
Q

Power (W) =

A

(current)2 (A) x Resistance (Ω)

37
Q

As with any energy transfer, some energy will be transferred usefully and some energy will be ….

A

wasted

38
Q

Energy transferred (J) =

A

Power (W) × Time (s)

39
Q

Energy transferred (J) =

A

Charge flow (C) x Potential difference (V)

40
Q

Step-up transformers are used to ….

A

Increase the potential difference and decrease the current.

41
Q

Step-down transformers are used to ….

A

increase the current and decrease the potential difference.

42
Q

Describe what would happen if two like charged particles were placed near each other.

A

Two like charges would repel away from each other.

43
Q

A balloon is rubbed on a jumper.
The balloon becomes positively charged.
Explain why the balloon gains a negative charge.

A
  • Electrons move from the jumper to the balloon.
  • So there are more negative charges on the balloon than positive charges.
44
Q

What is an electric field?

A

the space around a charged object that will exert a force upon another charged object that is placed there