Electricity (topic 2)

Question 1

Alternating current

Answer 1

current flow consisting of charges that continually change direction

Question 2

Ammeter

Answer 2

device connected in series with a component to measure the current that flows through it

Question 3

Ampere (Amp)

Answer 3

unit of current

Question 4

Circuit breaker

Answer 4

safety device that cuts off the power supply if a source of current passes through it

Question 5

Conductor

Answer 5

material that allows electrical charge to flow easily

Question 6

Coulomb

Answer 6

unit of charge

Question 7

Currents at a junction

Answer 7

sum of currents entering a junction must always equal the sum of the currents leaving it

Question 8

Diode

Answer 8

component that only allows current to flow through in the forward direction

Question 9

Direct current

Answer 9

consisting of charges flowing in a single direction

Question 10

Earthing

Answer 10

removal of excess charge by providing a low resistance path for electrons to flow through

Question 11

Earth wire

Answer 11

green and yellow striped safety wire connected to metal casings

Question 12

Electric current

Answer 12

rate of flow of electrical charge

Question 13

Energy transfers in circuits

Answer 13

electrical energy is transferred to thermal energy when current does work against a resistance

Question 14

Filament lamp

Answer 14

light emitting component consisting of an enclosed filament

Question 15

Fuse

Answer 15

safety device consisting of a thin metal filament that melts and cuts off the power supply if there’s a surge in current

Question 16

Insulator

Answer 16

material that doesn’t allow electrical charge to flow

Question 17

LDR

Answer 17

light sensitive component whose resistance decreases as its temperature increases

Question 18

Light emitting diode

Answer 18

device that gives out light when a current flows through it and can only flow through in one direction

Question 19

Live wire

Answer 19

brown coloured wire that carries the alternating current from the supple in a mains power supply

Question 20

Mains electricity

Answer 20

a.c. supple which in the UK has a frequency of 50Hz a value of 230V

Question 21

Neutral wire

Answer 21

blue coloured wire that completes the circuit in a mains power supply

Question 22

Ohmic conductor

Answer 22

conductor whose current flow is directly proportional to the potential different across it when help at a constant temperature

Question 23

Ohm

Answer 23

unit of resistance

Question 24

Ohms law

Answer 24

current flowing through ab Ohmic conductor at constant temperature is directly proportional to the voltage across it

Question 25

Parallel

Answer 25

same voltage across each component

Question 26

Potential difference

Answer 26

energy that is transferred per unit charge between 2 points in a circuit also called voltage

Question 27

Power

Answer 27

rate at which an appliance transfers energy

Question 28

Resistance

Answer 28

measure of the opposition to current flow

Question 29

Resistors in parallel

Answer 29

total resistance is less than the lowest individual resistance

Question 30

Resistors in series

Answer 30

total resistance is equal to the sum of the resistance of the individual resistors

Question 31

Series

Answer 31

components connected in series have the same current passing through each component but share the total voltage of power supply

Question 32

Thermistor

Answer 32

temperature dependent component whose resistance increases as its temperature decreases

Question 33

Volt

Answer 33

unit of potential difference

Question 34

Voltmeter

Answer 34

device that is connected in parallel with a component to measure the potential difference across it

Question 35

Watt

Answer 35

unit of power