topic 2 (electricity) Flashcards Preview

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Flashcards in topic 2 (electricity) Deck (14)
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1

what is current

flow of electrons

2

what is potential difference

driving force that pushes current around the circuit

3

what is resistance

anything that slows down the flow of the current

4

series circuit:

-current is the same throughout the circuit
-pd is split across components
-resistance is all the resistance added together (R1+R2....)

5

parallel circuit:

-total current is split across branches
-pd is the same across each branch
-resistance = 1/R1+1/R2.....

6

AC & DC

Alternating current is a current that periodically reverses direction
Direct current is a current that always flows in the same direction

7

Mains electricity in the UK

230v and 50Hz

8

the national grid

the national grid is how we get electricity from power stations to our homes

power stations -- step up transformer -- pylons -- step down transformer -- homes

9

plug socket

Has three main wires :
-live wire
-the neutral wire
-the earth wire

10

live wire

the live wire is the brown wire - it carries high pd into and around the house , the live wire is always connected to the fuse plug

11

the neutral wire

the neutral wire is the blue wire , it is close to the earths potential and it has no current in it until it is connected to an electrical appliance

12

the earth wire

the earth wire is a safety wire there is normally no current in it

13

static electricity

when we have static electricity we have an object that is not normally charged become charged , which happens when two insulators rub against each other

here the move from one thing to another causing it to be charged

14

equations

E=pt (Energy trans[J], power[W] ,time[s])
E=Qv (Energy trans[J], charge flow[c] , pd [v])
p=vI (power[W], pd[v] , current[A])
p=I^R (power[W] , current [A] ,resistance [ohms])
v=IR (PD[v], current[A] , resistance[ohms])
Q=IT (charge flow [c], current[A] , time {s])