Summary AQA A Level Physics revision poster - ELECTRICITY

In characteristics
current-rate of fow it charge
-

I = 11 -circuit used to investigate the current and

I

positive lo regative in conventional current
Power
A -
Pd g tre resistor using a variable resistor




-
flows from
-




P= PR
P IV , P VYR
=
=

between
potential difference
, -
-
The current exises because or a

one end and the other Power is the (P= e/t) ... = IVT I -

A piece es metal at a constant
temperative
rate of energy transfer
potential difference -
w
-
-
A resistor

(voctage) Q try onnic conductor (ebep onn's
raw)
Potential dividers
per charge
te mount o energy transferred
-




carrier
911
-



using te relative size e He resistere in (I & V provided there are constant physical conditions)
resistor spect the pd
each we ca ther
↑
-

a
bigger pal a
bigger wiret
-


~


#*
divided
difference component,
I RI
resistance ratio of potential across the -

An example of a
potential divider circuit R however ,
Ohm's law - =




by grad
the cur re in the component is en external change a
chage the internal
I


-
resistance x




#
-

filement bui
e .
9
A
- (LDR) M resistence point




>
at
-
=
-




~ eny

E
excromotive force -E >v




&
=


,


(emf)
-



energy pasferred to
e g by battery
the circuit
A


y
. a
I
diode




↑
-
- -



current direction
only flows is I




electricity
&




Resistivity
Re conductors
+


>v


If
you have wire with certain resistere it depenses
Cicuits
a a




↳
be its legen




X
↓
.




e
. if charge is conserved
-




g you double the
length you double resistance
.

the

because where ↑
is more to slow down the cverge carriers Ii= I out & Kirchoff's 1st
However
If you increase the crea
juncra
,
the resistance law
as seeire is thicker and
,

there is
decreases : Elin
=


Elout ir a
more
space for te charge
carriers to How through Internal Resistance energy is also
conserved

resistivity things line I
↑
Internal resistance


A
am can corre from closed circuit
p
=
in in a

resistance crenicals a
battery ,


EE SV
911
=

crece
m2 resister
x nor an annual
---
~R
egt

fi
m -it
11 I
-

just represents
the
-
E Series circuit rules : v R
..... L
internal resistance
As the
temperature increases so does ste resistance .
This is
2
=

I(R +
r)
-> the current

(since there
is the some at a l l

junctions)
points Er V2

grad
are so
because the undert cat
flow as fast because the
particles T
- terminal pd
iside wire
-> emt is split between components (ent =
V +
V2 +



Vz )
moving
,
the are
to slaw He
...


fast enough charge v =
E
# -
> ->
if v is constant , is IR
down /crease rsistener) -



I
so (emt : IR ,
+(R2+IRz ...
)
the greater the current
flowing , concelling
->

out
the less the terminal p d the I's give RCroral) R,
+R2+Ry
=
.




wher conductors because
reated the current inside the cell meas that
.



are more electors have
,
enough a smaller

energy o be viberated so the resistance has a
bigger erect
In charge flows faster .


a
negative temperance
resistance
ficient (NTC) Hermistor Parallel circuit rule :

dureases In series -> total internal registance is
)
with

the sum
temperature ->
current is split at each
junction (F total = 1 , +12 +13 ...




· all the internal resistances of the
RA when cooled to a 'critical temperature' a
->

pd is the across all comparers
same E
wire will become
a
cees (ine more cells
, ~4)
super conductor -> V/R YR
where it is
YRe+ YR
:



toral +
cooled to the
In parallel -> the
,
3
point
...

where there is more cells there are W
no vibration in ,
internal
->
He particles and He resistance decreases cancelling the v's give
resistere is zero IT
---
> I
I (The more caus , ri) Rosal
=



E, z s
...




-Hiy