Electricity Flashcards
what is current and what is it measured in
measure of flow of electrons around a circuit AMPS (A)
What is potential diffrence/ voltage
driving force of the flow of electrons( current)
measured in VOLTS
what is resistance
Everything that resists or opposes flow of electrons in OHMS
which way does current flow
From the positive terminal to the negative terminal
(right to left)
what is ohms law equation!!!
V= IR
VOLTAGE = CURRENT X RESISTENCE
what does the ohms law show about relationship between current and voltage
as long as resistance remains constant, if we increase voltage then the current will increase proportionally
is voltage directly proportional to current
YES
DIAGONAL STRAIGHT LINE
what are we assuming in ohms law
that temp stays constant
what is a series circuit
one loop
what happens if one component of a series circuit stops working
the whole circuit stops working
how do you work out voltage in series
It’s shared equally to all components
V1 + V2 + V3 = V total
how do you work out current
same through all components
can also rearrange ohms law to calculate current
how do you work out resistence in series
total resistence = sum of all individual resistence
what is the equation for charge flow
Charge flow = current x time
what is charge flow measured in
Coloumbs (C)
what is parralell circuit
has more than one loop
what happens if one component breaks in a parralell circuit
it stays intact
how do you work out voltage in parralell
same through all components
how do you work out current in parralell
shared through all loops
I1 + I2 + I3 = I total
What will loops have if they have a greater resistance
A lower share of the current
what is mains electricity
refers to the power that is brought to peoples homes
230 V
50 Hz
What does AC stand for and does it have Alternating direction
Stands for Alternating current
Yes
What does DC stand for and does it have one direction
Direct current
YEA
what are the three wires in a plug
Live - brown
neutral - blue
green - earth
what does the fuse do
melts if the current is too high
when is the demand for energy the highest and why
Late afternoon as people are coming home from work and shchool
what does the step up transformer do
Increases voltage
What do step down transformers do
Decrease voltage to a safe level
What is the route of the national grid
Power stations —-> step up transformer —-> transmission cables —-> step down transformer ——> homes
why do we need a low current
Reduce heat energy being lost by surroundings
It’s dangerous
And can Burst appliances
what level volts are transferred to your home
230 V
what is static electricity
build up of charge on insulating materials
do all materials contain charge
yes
mostly neutral
as protons and electrons cancel
what happens when materials are rubbed against each other
causes friction
which moves electrons from one object to be transferred to another
does charge build up in conducting material
no
so static electricity can’t happen
What happens when you rub a polythene rod to a cloth
The rod gains electrons and becomes a negative static charge
The cloth loses electrons and becomes a positive static charge
Friction created
electrons transferred from cloth to rod
In static electricity do you talk about the transfer of protons or electrons
Electrons
What happens when size of charge increases
Potential diffrence builds up between material and earth
which plug, live neutral(blue) or earth wire is in the middle
EARTH (YELLOW AND GREEN)
WHAT IS RHE POTENTAIL DIDFENRCE BETWEEN NEUTRAL WIRE AND EARTH WIRE
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