electricity ✓

Question 1

what is the symbol for current ?

Answer 1

I

Question 2

what is the symbol for energy ?

Answer 2

Q

Question 3

what is the symbol for charge ?

Answer 3

E

Question 4

what is the symbol for resistance ?

Answer 4

R

Question 5

what is the symbol for voltage ?

Answer 5

V

Question 6

what is the symbol for power ?

Answer 6

P

Question 7

what is current measured in ?

Answer 7

amperes/amps (A)

Question 8

what is charge measured in ?

Answer 8

coulombs (C)

Question 9

what is energy measured in ?

Answer 9

Joules (J)

Question 10

what is resistance measured in ?

Answer 10

ohms (Ω)

Question 11

what is time measured in ?

Answer 11

seconds (s)

Question 12

what is voltage measured in ?

Answer 12

volts (v)

Question 13

what is power measured in ?

Answer 13

Watts (W)

Question 14

what is current ?

Answer 14

it is a measure of the rate of flow of charge

Question 15

what is voltage ?

Answer 15

the energy transferred per Coulomb of charge

Question 16

what is electric current in a wire or metal conductor ?

Answer 16

the flow of electrons

Question 17

what is the equation for charge ?

Answer 17

charge = current x time

Question 18

what is the symbol equation for charge ?

Answer 18

Q = I x t

Question 19

what materials are conductors ?

Answer 19

metals

Question 20

what materials are insulators ?

Answer 20

plastic

Question 21

what does the current in a series circuit depend on ?

Answer 21

the applied voltage and resistance of the components

Question 22

what is the equation for voltage ?

Answer 22

voltage = current x resistance

Question 23

what is the symbol equation for voltage ?

Answer 23

V = I x R

Question 24

in a series circuit what is the current strength ?

Answer 24

the current is the same at every point

Question 25

in a parallel circuit what is the current split between ?

Answer 25

the arms of the circuit

Question 26

in a series circuit what is the voltage split between ?

Answer 26

each of the components

Question 27

in a parallel circuit what is the voltage at each component ?

Answer 27

it is the same

Question 28

how does current vary for a fixed resistor ?

Answer 28

potential difference is directly proportional to the current

Question 29

how does current vary for a wire at constant temperature ?

Answer 29

current through a metallic conductor is proportional to the potential difference across it if the temperature remains constant

Question 30

how does current vary for a filament lamp ?

Answer 30

the current flowing through a filament lamp is not directly proportional to the voltage across it

Question 31

how does current vary for a wire ?

Answer 31

as more components are added the current decreases

Question 32

how does current vary for a diode ?

Answer 32

if the potential difference is arranged to try and push the current the wrong way no current will flow as the diode's resistance remains very large

Question 33

how does current in a wire or filament lamp transfers energy to it ?

Answer 33

energy gets transferred to the component which causes it to heat up. This is used in light bulbs to make the room lighter and is used in electric heaters

Question 34

what does the gradient of a graph of voltage against current graph show ?

Answer 34

it gives the resistance steep means high resistance shallow means low resistance

Question 35

what can lamps and LED's be used for ?

Answer 35

to indicate the presence of current in a circuit

Question 36

why is a series of parallel circuit more appropriate for domestic lighting ?

Answer 36

series circuits are used more in fairy lights because they light the whole series of lights in one whereas parallel circuits are more useful for lighting in rooms because if one breaks only one light stop working instead of all of the lights in the house to stop working

Question 37

how do fuses work ?

Answer 37

- if a fault develops which the live touches the metal case - because case is earthed large current flows through the live, through the case and out of the earth wires - surge in current blows (melts) fuse which cuts of live supply - this isolates the whole appliance and makes it impossible to get and electric shock from the case and prevents risk of fire

Question 38

how does earthing work ?

Answer 38

earthing means that the case must be attached to an earth wire. The earth conductor never becomes live and directs the live to the earth wires

Question 39

what is the symbol for double insulation ?

Answer 39

square inside another square

Question 40

what do double insulated appliances not require ?

Answer 40

earth connections

Question 41

why do double insulated appliances not require earth connections ?

Answer 41

- the plastic is an insulator | - stops current from flowing

Question 42

what are the advantages of using a circuit breaker over a fuse ?

Answer 42

- when circuit breakers detect a surge in current they break the circuit by opening a switch - circuit breakers can be easily re-set so more convenient because fuses have to be replaced

Question 43

what is the equation for power ?

Answer 43

power = current x voltage

Question 44

what is the symbol equation for power ?

Answer 44

p = I x V

Question 45

what is the equation for the energy transferred ? (given in exam)

Answer 45

energy transferred = current x voltage x time

Question 46

what is the symbol equation for the energy transferred ? (given in exam)

Answer 46

E = I x V x t

Question 47

what is the equation for energy ?

Answer 47

energy = charge x voltage

Question 48

what is the symbol equation for energy ?

Answer 48

E = Q x V

Question 49

what is the difference between AC current (alternating) and DC current (direct) ?

Answer 49

``` AC = current is constantly changing directions DC = current stays in same direction ```