ELECTRICITY

Question 1

current def

Answer 1

rate of flow of charge

Question 2

def voltage / p.d.

Answer 2

force driving the flow of electrons
provided by cell/battery

Question 3

resitance def

Answer 3

everything that resists or opposes the flow of electrons

Question 4

whats the graph for resistor (V = IR)

Answer 4

straight line, through (0,0)

Question 5

graph for filament bulb V = IR

Answer 5

curvy line , goes through (0,0)

as it heats up, which increases resistance

Question 6

graph for diode

Answer 6

lying on x axis until it curves up when the p.d is positive
vvv. high resistance in reverse direction so no current flows
as diodes only allow current to flow in one direction

Question 7

charge def

Answer 7

a measure of the total current that flowed within a certain period of time

Question 8

what can switches be used for

Answer 8

controlling the flow of electricity

Question 9

purpose of diode

Answer 9

only allow current to flow in one direction

Question 10

purpose of fuse

Answer 10

break if too much current

Question 11

symbol for fuse

Answer 11

rectangle w line through it

Question 12

A light emitting diode will: (2 things)

Answer 12

Emit light when current flows through it

Only allow current to flow in one direction

Question 13

symbol for LDR

Answer 13

circle w rectangle inside w two arrows pointing to it on left

Question 14

symbol for thermistor

Answer 14

rectangle w line through it that is horizontal underneath recatngle

Question 15

symbol fr variable resistor

Answer 15

rectangle w arrow through it pointing up

Question 16

Which type of resistor allows us to easily adjust its resistance?

Answer 16

variable resistor

Question 17

A resistor which cannot vary the amount of resistance it provides is a:

Answer 17

fixed resistor

Question 18

The resistance of a thermistor decreases when the temperature _______.

Answer 18

increases

Question 19

p.d and resistance is what in a series circuit

Answer 19

shared across all components
v(total) = v(1) + v(2) + …

Question 20

what is ohms law

Answer 20

V = IR
(series)

Question 21

In a series circuit, the current is:

Answer 21

the same everywhere in the circuit

Question 22

In a series circuit, components with a greater resistance will always have a ________ share of the voltage.

Answer 22

greater

Question 23

pd. is what in a parallel circuit

Answer 23

the same across all components
v(1)=v(2)=…

Question 24

what is current in a parallel circuit

Answer 24

shared across all loops
I(total)=I(1)+I(2)+….

Question 25

total resistance _______ when you add more resistors in parallel

Answer 25

decreases 1/R(total) = 1/R(1) + 1/R(2) + ...

Question 26

purpose of step-up transformer

Answer 26

increases voltage, decreases current reduces energy loss

Question 27

step down transformer purpose

Answer 27

decrease voltage, increase current makes it safe 230V

Question 28

uk mains supply values

Answer 28

50Hz 230 V

Question 29

True or false? Alternating current is caused by an alternating potential difference.

Answer 29

true

Question 30

The role of an oscilloscope is to:

Answer 30

display how voltage changes w time

Question 31

colour and role of live wire in plug

Answer 31

brown wire - 230V alternating potential difference

Question 32

colour and role of blue wire in plug

Answer 32

blue wire complete the circuit by carrying away current pd of 0V

Question 33

colour and role of earth wire

Answer 33

green and yellow wire safety wire doesnt carry current stops the appliance casing from becoming live (if live wire got lose touched case) 0V

Question 34

wires are mad of what and coated in layer of insulating what

Answer 34

copper, plastic

Question 35

Which wire supplies the current to the appliance?

Answer 35

live wire

Question 36

Which wire completes the circuit, allowing current to flow?

Answer 36

neutral

Question 37

how do fuses work

Answer 37

thin peice of wire that melts when current gets too high, breaking the circuit so no more current can flow

Question 38

pros and cons of fuses

Answer 38

pros - simple and cheap cons - permanently broken after single surge so have to be replaced each time

Question 39

true/false - you always want the fuse a couple amps above the appliances current

Answer 39

true

Question 40

how do circuit breakers work

Answer 40

get tripped whenever theres a surge so turn off the circuit

Question 41

pros and cons of circuit breakers

Answer 41

pros - can be reset so dont have to be replaced cons - more expensive than fuses

Question 42

how do earth wires prevent harm

Answer 42

provide an alternative pathway so any electricity is diverted through the earth wire

Question 43

how does double insulating work

Answer 43

covered in plastic casing (no exposed metal parts) and plastic doesnt conduct elec. so cant get elec shock

Question 44

what is static elec

Answer 44

Static electricity is the build-up of electric charge on the surface of an object, usually caused by friction.

Question 45

how does static charge build up

Answer 45

When two insulating materials are rubbed together, electrons are transferred from one to the other. 🔹 Gain electrons = becomes negatively charged 🔹 Lose electrons = becomes positively charged

Question 46

which materilas get charged from static elec

Answer 46

Only insulators (like plastic or rubber) hold static charge. Conductors let charge flow away, so they don’t build up static.

Question 47

what is ionisation

Answer 47

🔹 Ionisation is when an atom gains or loses electrons, forming an ion. 🔸 Loses electrons → becomes a positive ion 🔹 Gains electrons → becomes a negative ion

Question 48

feild lines always point from ...

Answer 48

positive to negative charge

Question 49

A strongly charged object can ionise the air, which means the air:

Answer 49

conducts elec loses some of its electrons