Electricity Flashcards
what is electric current. A, Ampere
flow of electrical charge, C, Coulomb
are electrons negative
yes
chargle flow equation
charge flow + current x resistance
what is resistance
measure how it resists (oppose) flow of charge. - ohms, R
what is potential difference.
electrical potentail from 1 point to another. V, Volts.
increase and higher resistence =
more diffcult charge flow + reduce current.
increase and bigger potentail difference =
greater flow of charge + increase current .
current through component depends on?
resistance and potential difference
what is potentail dfference in parall and series.
parallel= each component same
series=all add up to total amount.
ohmic conducter means
current is directly propotional to potentail differenc.e
what happens to resisance in fixed resistor.
restaince constant as temperature and current change.
what is diode
current flows in 1 direction.
what are main 3 wires and colour
live - brown
neutal- blue
earth-green and yellow stripe
what are the 3 wires made out
out of copper and layer of coating plastic
what is live wire
alternating potentail difference of 230v main supply.
connects to fuse in plug
what happens if live wire loose
it will touch the casing and give electric shock as human have 0v making larger current flow of shock.
what is neutral wire
completes the cirucit by carry away current. 0V
what is earth wire
stops appliances casing from become live 0V.
provides alrnerating path for current to flow away than to use.
resistance equation
restaince = potential differnece / current
energy transfer, charge flow ewuation
energy transfer = charge flow x potnetial difference
why can we use therimsotor as thermostat, exmaple.
because device can turn on/off dependng on temperaure, likewise incubator for premature baiebs.
complete this - therimoster
low tempertaure =
high temerpatire=
high resistance beause alot enegry needed to pass through.
low resistance.
LDR complete + why
low light, dark =
high light, low =
high resistance cos use energy for current to pass
low resistance cos take litle energy for current to pass thriugh.
LDR exmaples
garden light, street light, security
what is series cirucit and is it ammeter or volt.
connected one after then other with same current each component. - ammeter
what happens to resistors in series when add more.
it will increase totola resistance.
what happens to potential difference in series
total pd of the power supply is shared between the components.
wht is parallel circuit
connected side by side on seperate path, voltmeter.
what is the current on parallel circuit
current split proportion for each compoent.
what happens to the potentail difference in paralle
thepotentialdifference across each component is the same
what happens when adding resistors in parallel
reduces the totol resistance
what do LED give off
light and energy effiecnet
what is oscilloscope
display how voltage change with time.
what is D.C and stand for
direct current of contineous electric current flow 1 direcetion.
how does D.C look like on oscilloscope and where supplied in
straight line and cell/batteries.
what is A.C and stand for
Alternating current, contineous electric current in reverse.
where is A.C supplied in and oscilloscope.
Main supply in National Grid 50Hz, 230V, like up and down repetion.
Domestic appliances types
blender, iron, kettle, wash machine, fan, hairdryer
Appliances to transfer kinetic and thermal.
Blender (400w) and Fan(20w) by kinetic energy of electric motor as both appliances movement. And thermal by fricition enters.
another 1 appliances of transfer kinetic and thermal
Hair dryer and Wash machine, kinetic energy of elctric motor as heat water under motor turns the drum to wash. And thermal as it is both heating element.
power, current, resistance equatio
power=(current)2 x reisistance
what is a National Grid
sytem of cables and transformer of electric current and voltage for safely arrive to consumer.
the bigger distance bwteen power station and home, what happens, and reduce how.
greater energy loss due to resisitance of wire + reduce by build power station near homes and trnasformer.
what happens to step-up trnasformer and why.
increase potentail difference because less energy is lost in power cabels. AND decrease current.
what happens to step-down transformer and why.
reduce potential difference because for home to use for safety than applaince blow. AND increase current.
what is electrically charge
insulating materals rubbed each other
what happens when object gain electron AND, object loses electron
Negatively charge AND postive charge
what is isolated object
no conducting pathway to earth
what happens when there is charge on isolated object
increase potentail difference to cause spark occur
what is attraction
2 object carry different charge attratcs.
what is repulsion
2 object carry same charge repel.
what is electric field
area around charged object that will effect other object
when is elctric field strongest AND weakest.
charged object close is strongest AND furhter away charge object is weaknes.
what happens when a man touch the dome of generator
man is postive charge because hair goes up as they all repel each other as each hair is postively charged.
what happens when rub cloth and plastic rod insulator
electrons move from plastic to cloth
why increase p.d and what happens to the current.
Increasing p.d decrease the current. So the smaller current means less energy changed to thermal energy in cabels
why national grid system is efficient for energy transfer
It involves high voltage and low current to minmise energy loss of heat in power cables. Then step down transformer reduce voltage and increase current for safety of households, shops.
why add resistors in series increases total resistance
adding resistors is increasing resistance, this make it difficult for charge flow for current.
