electricity (p1)

Question 1

What is the circuit symbol for a bulb?

Answer 1

Circle with a cross

Question 2

What is the circuit symbol for a cell?

Answer 2

Two lines, one shorter than the other

Question 3

What is the circuit symbol for a battery?

Answer 3

Two lines, one shorter than the other, repeated at least twice

Question 4

What is the circuit symbol for an ammeter?

Answer 4

Circle with an A

Question 5

What is the circuit symbol for a voltmeter?

Answer 5

circle with a V

Question 6

What is the circuit symbol for a switch?

Answer 6

break in the wire line

Question 7

What is the circuit symbol for a fuse/resistor?

Answer 7

Rectangle with a line through

Question 8

What is the circuit symbol for a diode?

Answer 8

Circle with an arrow and line inside

Question 9

What is the circuit symbol for a LED?

Answer 9

Circle with an arrow and line inside and two arrows pointing out

Question 9

What is the circuit symbol for a resistor?

Answer 9

rectangle

Question 10

What is the circuit symbol for a variable resistor?

Answer 10

Rectangle with an arrow through

Question 11

What is the circuit symbol for a thermistor?

Answer 11

Rectangle with a bent line through

Question 12

What is the circuit symbol for an LDR?

Answer 12

Rectangle with a circle around and two arrows pointing in

Question 13

What is the function of an electrical cell?

Answer 13

Provides energy to the electrons, or provides potential difference

Question 14

What is the function of a battery?

Answer 14

Provides energy to the electrons, or provides potential difference

Question 15

What is the function of a fuse?

Answer 15

Breaks and stops the circuit if the current is too high

Question 16

What is the function of a switch?

Answer 16

Breaks or completes the circuit

Question 17

What charge do electrons have?

Answer 17

negative

Question 18

What equation links current, charge flow & time?

Answer 18

charge flow = current × time

Question 19

What is the unit for charge flow?

Answer 19

Coulombs, or C

Question 20

What is the unit for current?

Answer 20

Amps, or A

Question 21

What is the unit for time?

Answer 21

seconds

Question 22

What happens to current flow if the resistance increases?

Answer 22

decreased

Question 23

What is the unit for potential difference?

Answer 23

volts

Question 24

What is the unit for resistance?

Answer 24

Ohms, or Ω

Question 25

What is the function of an ammeter?

Answer 25

Measures the current in a circuit

Question 26

What is the function of a voltmeter?

Answer 26

Measures the potential difference through a component

Question 27

Where should an ammeter be placed in a circuit?

Answer 27

Ammeters should be placed in series with the components

Question 28

Where should a voltmeter be placed in a circuit?

Answer 28

Voltmeters should be placed on a parallel bridge around the component of interest

Question 29

What is the function of a resistor?

Answer 29

Increases the resistance of a circuit

Question 30

What is the function of a variable resistor?

Answer 30

Increases the resistance of a circuit, and can be changed

Question 31

What is an ohmic conductor?

Answer 31

The current through an ohmic conductor (at a constant temperature) is directly proportional to the potential difference across the resistor. This means that the resistance remains constant as the current changes.

Question 32

What does the current-potential difference graph for an ohmic conductor (like a resistor) look like?

Answer 32

A straight line through 0,0

Question 33

What does the current-potential difference graph for a filament bulb look like?

Answer 33

A curved line through 0,0

Question 34

What is the function of a bulb?

Answer 34

Produces light radiation

Question 35

What does the current-potential difference graph for a diode look like?

Answer 35

A curved line that increases significantly after a certain potential difference

Question 36

What is the function of a diode?

Answer 36

Allows current to only flow in one direction

Question 37

What is the function of an LED?

Answer 37

Allows current to only flow in one direction, and produces light radiation

Question 38

What happens to the resistance of a thermistor when the temperature changes?

Answer 38

The resistance of a thermistor decreases as the temperature increases.

Question 39

What is the function of a thermistor?

Answer 39

Increases the resistance of a circuit depending on the temperature of the surroundings

Question 40

What happens to the resistance of an LDR when the light intensity changes?

Answer 40

The resistance of an LDR decreases as light intensity increases.

Question 41

What is the function of an LDR?

Answer 41

Increases the resistance of a circuit depending on the brightness of the surroundings

Question 42

How are thermistors used?

Answer 42

in circuits as thermostats

Question 43

How are LDRs used?

Answer 43

in circuits to switch on lights on when it gets dark

Question 44

Give four examples of non-ohmic conductors

Answer 44

Diodes, filament bulbs, LDRs, thermistors

Question 45

What is the unit for power?

Answer 45

Watts, W

Question 46

What does the amount of energy an appliance transfers depend on?

Answer 46

how long the appliance is switched on for and the power of the appliance

Question 47

What is the unit for energy transferred?

Answer 47

joules

Question 48

What is the unit for work done?

Answer 48

joules

Question 49

[𝗛𝗶𝗴𝗵𝗲𝗿 𝗧𝗶𝗲𝗿] In a transformer, which coil is the primary coil?

Answer 49

The coil with an alternating power supply connected to it

Question 50

[𝗛𝗶𝗴𝗵𝗲𝗿 𝗧𝗶𝗲𝗿] In a transformer, which coil is the secondary coil?

Answer 50

The coil without an alternating power supply connected to it

Question 51

What colour is the neutral wire?

Answer 51

blue

Question 52

What is name of the blue wire in a plug?

Answer 52

neutral

Question 53

What colour is the earth wire?

Answer 53

Green and yellow stripes

Question 54

What is name of the green and yellow striped wire in a plug?

Answer 54

earth wire

Question 55

What colour is the live wire?

Answer 55

brown

Question 56

What is name of the brown wire in a plug?

Answer 56

live

Question 57

What is the purpose of the neutral wire?

Answer 57

Completes the circuit

Question 58

What is the purpose of the live wire?

Answer 58

Provides the alternating potential difference

Question 59

What is the purpose of the earth wire?

Answer 59

Protects the circuit and stops the appliance casing from becoming live. It only carries current if there is a fault.

Question 60

What is the pd of the neutral wire?

Answer 60

0 V

Question 61

What is the pd of the live wire?

Answer 61

230 V

Question 62

What is the pd of the earth wire?

Answer 62

0 V

Question 63

What is the national grid?

Answer 63

a system of cables and transformers linking power stations to consumers

Question 64

What is the potential difference of mains electricity?

Answer 64

230 V

Question 65

What is the frequency of mains electricity?

Answer 65

50 hertz

Question 66

What type of current is mains electricity

Answer 66

Alternating current (caused by an alternating potential difference)

Question 67

What is direct current (d.c.)?

Answer 67

Current flows in one direction around the circuit, due to a direct potential difference. It is supplied by cells and batteries

Question 68

What is alternating current (a.c.)?

Answer 68

Current changes (alternates) direction, due to a potential difference where the positive and negative ends alternate. It is supplied by mains electricity

Question 69

Why does the national grid transmit electricity at very high potential differences?

Answer 69

Less energy is lost, which makes it more efficient

Question 70

What happens at step-up transformers?

Answer 70

potential difference increased (current lowered)

Question 71

What happens at step-down transformers?

Answer 71

potential difference lowered (current increased)

Question 72

Why do we need step-down transformers?

Answer 72

Electricity has to be reduced to mains potential difference (230V) to be safe for use in homes