random booklet stuff Flashcards
current definition
the rate of flow of charge
if component x and y are in series how does current flow
it must pass through x before passing through y
if component x and y are in parallel how does current flow
current passes through x and y at the same time
how do we measure potential difference
voltmeter
what provides pd in a circuit
the battery
what makes a battery
two or more cells in series
what is resistance a measure of
how difficult it is for current to flow through the component
the higher resistance the —— it is for pd to push charges
higher resistance = harder for pd to push charges
what does ohmics law state
current is directly proportional to pd
what effect does thermistor have on resistance
higher temp lower resistance
ldr effect on resistance
higher light intensity is lower resistance
thermistor effect on current
higher temp higher current
ldr effect on current
higher light intensity higher current
what will current be like in series and why
same at all points
bc same amount of charge will pass through every point every second
potential difference in series circuit
total pd in battery = sum of pd of other components
how does current flow in parallel
split between branches of circuit
current rule in parallel
current in battery = sum of current in branches
what is pd a measure of
how much energy each coulomb of charge receives from battery
how much energy each coulomb loses when it passes through something
pd rule for parallel
pd in battery = pd in each branch
resistance rule in parallel
total resistance of circuit is lower than the resistance of the branch with the lowest resistance
what does dc stand for
direct current
how does charge flow in dc
one direction
how does pd flow in dc
remains in constant direction
what does ac stand for
alternating current
how does charge flow in ac
backwards and forwards
how does pd flow in ac
it alternates
which out of ac and dc is easier to transport
ac
what current is mains electricity
ac
what colour is the live wire
brown
what colour is the neutral wire
blue
what colour is the earth wire
yellow and green
what is the pd of live wire
230V
pd of earth wire
0V
pd of neutral wire
0V
what does the live wire do
carries current to appliance
what does the neutral wire do
completes the circuit
what does the earth wire do
its just for safety ☹️☹️
what does the cable grip do
prevents cable pull out
why should live wire never touch earth
the earth wire conducts current away if the casing becomes live
WTF DOESTHSI MENA
whats the national grid
system of cables and transformers that transports electrical power
what does the step up transformer do in national grid
increases pd = decrease current = low heating effect = minimises energy dissipation
what does step down transformer do in national grid
decrease pd to 230V for safe use in homes
what happens when insulating materials are rubbed against each other
they become electrically charged
one gains electrons one loses electrons
gain = negative charge
lose = positive charge
why do peoples hair stand up after becoming charged
each strand of hair has the same charge so they repel each other
what do field lines show
direction of positive charge
how do field lines change according to the strength of force
more field lines = stronger force
whats sparking
sorry i dont get sparking 😋😋
