· 5. Elec+irici+y ond m0-~ ne+i6m
5i Electric ~-1dJs
E le.crnc cha~ .
-s'1rnbo\ ,_ Q
unit: C (courom'b)
i
1)-r,0~1nve.
.
ne.S\a.twe. (\i\<.es tt~e..\ Jo,?O~'\e..'.:> o.t\ro.c+')
(pro\ons")
1) ·, s
(ele.i \wns")
co.nse.rved.
=1
co.N'to\- l:,e c..re.o,.,kc,l
or Je.~®'-fed..
3)1'> ':i')Of\\i1,eol --::'yame'> ,n J;scte--\e
e..ledmn
Ex .
e =e\emeomr'(
-e
\"'d.a.•~t'''
cn1e
Dmton = +e
1
-= -1Gxl0 ~C.. (coulot'l\b)
= t1 Cox10Jc..
=
1
1
1oto.l c\rio.1{- = +~e.- 2e -.le.."' 3.l x16 ~C.
Cou\ornb'~ Lo..w
· s-z.e o~ +he. electric
c00\ombl ( ~S.'3~J1IO")
cof'l':i'°-1"1 l
~,ie o~
(
cho.ries
,--------t----=.:....../--,
F==
K
I
rl
2
J;::,tcmce
be\-we.en ~ 1
'
a"J ':\t
r= 1rn
f-:::
-0
-1".)
f= -z
'3:Y:lxlOeix. 1Gl(IO x}\b,clO -::. 5xlO,.gtJ
1
eledric. per,ni#iviJy
• 2iorne.:hmes
&
wcuum
( iasx l6'i)
I
.,- .- - - - - 7
~,5-1-,
viF=J__
:
i,1Tf 0
(1.
I
l....---- ___
_j
Ex
F-=- ~)( i.i5xl6 iJ
1
- -
E\e.c-\nc tie.\J
F,e\J. = ever,/ f01f1l ,n 5face has
E. d. ''1 r r'll-pero:tuve.. ,\\ d J
o... 'IJu.m~e.r
ve.<e'kl r)
i.,.
X '\
,I( 31
,f
.1(}1,1
\
~a. \o.r
e\c;l
e\e.cJric. ~e\J.
5'rte,~th r ' "
ne -.
F
Q ) •J'
(or
11
I
E =£
t
l:..
=
I
kQ3;
ri.
°\
\.,
1-
I'
=kQ
r1.
'I
6ne~ th of tield
-
0
Dire.c.:ho"
o~
o<.
\,ne. JenS\',
helJ. :::.o\ir«.non th~ ('cr-ce a.c:\"5 on
o_ ros."mve. chetie
- Li "'e~ ne..ve.. cross
- Li he~ r'nee+- o.. c.of\c1JC.f\n~ s,_;,r-kQ. a..t ~0
6
oQ. ~lec,tr\ci±-y_
~o E-t1eld
wi+h E-Ael&
<.
E
0 0-0li )
- random rnovetnef\ l
5
10
m/~
- f 6)-neJ&rn -roovemmt
ele:btrnn~ are sl<'--ult
t
Jn-tnn 0 ,~·1~:>tu the ~elJ
l)Jiliftrtveloc,~y
'
I '
Vn
rnrrf:>
Fine;
c.orrtn't ;amoont ot charae
paint- eac.h seconc:L
o.
1t.---+--C.l't)SS Secoonct \
c~~e.
~rit+ speed
tl'"'-'4.
per c.~e co.rrie.r
·
.
I=- ~Q
/ le.t Dt·=h
I=AQ
(inside c-,1.)
bt'
•
EK
I=1A
=
:tt:
-i>
~hwae cnrt.
V
e}ectrons
vol.
V x ChQ~C'.
ch.atrrie~
= 101.~ 1Y(1
o{ri-P+ '5-peect?
1.-=nAvq
1
2'6
-=
T
l
-l'J
10 '-lT-"'(2x1o~)x.V x.1.GxlO
-5
,·
-,
-'1V~5x/D ms-=05~m5
B
W=
f~ =m3h
,., h "r ct.".
fbeJweer,)
tAlB
A
w
=
'm
m•f
0rc. 10,~ - ('°indeP€ridenl
o~ ma.ss!)
I
clone. when person·~ mo.ss. iS
U-Jorl'-
50ki: W= 50 )(.1-0-= "35-00J
·'-io k~:
40 ,_ 1-0 = 2.'300J
u.J
G~n€ra.l (alu.P-yshut-) Horn0qeneous. ~elc.l.
-0
\
{I
0.1~
I
I
B (f
Wor~ Jroe. on the ch~e
w==GJ
vJ =bJ =31
2.C..
r-
E=S~
~ -;
'·.
A
c®
-
'
•
t
-
6-
e1ec+r-ons ~if) PE
lil-lle. PE i5
+
r?J
·1
J
PE= \6J
V-=
I
Circu,ts
(.,
=cN(1JO\l
+o the lo.-\lice
I ii'\ \-he wir-t
-1,I (.neo.+)
po-\enho:\ ~l~rence.: ele(.frica.l ,,....---._) li~nl, ( loo~pea.ker,I )
IC
, at v\
ene1'/
. hjoJ:,J
mol-or) larnp.)-p .) )
.. ,
e.\e.d'romotive torce.
e\ectrico.)
!
ene.f??\
ut
(pE ot elec..trons
En
~~-p~,~cl iyex- oC\·\~
' e.ctronvo t
e V= e,n~~ ~ained
0 p.ol.
br
l_ijYI~_, ~olar cel\.s J )
CH'em1cal, oo.1-1-eryJ
5CXJndv microphM1e 1_ • .
·· · .
C..,Y)os<;ie.
-
u
an e.ledmn when it moves +hro°(jh
o~ one. volt .
KE
of
+he
e_\ectrori when it hirs the
t
lo-k?
-I~
KE:W= V::1.bxl0-I~C,x1V = 1(.xlOJ
= 1e\edro/\u,11
----1i
.
V=1V
1
5.lHeo:hn~ eWect of on electric c_l)rrenl
• D,re_c+ con-ent (tx.):c
5.J ( heMiCc.\ \j
( 5 •½ mo..cf'e.t-41,
Cha.~ tlow in one. directio11
'Alkrfla.-nf'\i conot (AO-= clirtdiOr\ of +he current cho.n~es
( ~100 tme.~ /s)
Re<::iistunc.e..
=- ?ole_riha.\ olil'e.rence. o..c (0')':> t~e ~()0\t
(ri ex cornvonenl')
c..urre.nt '1n the_ com-po(\ef\t
~
.
L___!_1
- >
Ohm'~ lo..w
Ohm'~ lo.w : the ,-polenful dif~reoc~ o.cross
a_
me+oJ(ic
-pr~or\i
. 'ooa\ to the... c0crent
'1n the. co~tllX.t--or if 1its kmpero.tul'l- iS
COf\Jud-or
i"::i
Cofl :::itan t
Pol).)e r-
. Ene~
~=
oleliverwl to
\LI
Cl
conclu.c+-or
tr= f I \P=Rr1]
voltu~e.
ocrOSS
the c_ondoctor
eac.11 Se.c.oncl !
V
IL= V
I
I
) velocih is
th( slo£e.
'
ID
'l
re:;,stonce
ot the
wire
\e.n~th ot- the wire
-
cross sec. -\iooa.l o.rea..
L--~)
,es·1stjv i+~ o~ the ma-\-e.(10. \
YnCA~ria.1 coo~hnt \ik-e.
\
( olen~it-~ :i ~rec.iti•c h€rA.t- CufQd-1-)J
E)(.
-1.
mo.,v~
=-
=
/'\
'I
Iv-~
mm
paw~r ol;ssj~lf._d.
sr
==
'P=
=-
'2
'l.
.
·- :
,..-, g_~Y... .2lQ..-= 6~.l-01
. R-P 110
~~-101 )((ltx(:,x1011?2J
3.'884 xlo"
5
-= "11-0IJJ
x.16"S2
Comb, nin~ re6i~tor'.:l
c.urrern s ome
V
volh e Sarne
0
/ over ~Qlh
c.ornpaneM
in ea.ch
I , - - - - - - - - ' COrnjX)Oellt
.____,
L..L,,,......
v,
V2
Vl
Ex. To+al re.~.-,~ance.
·111
the.. c'ircuit'
..;, P\<;= 20 t IO: 30_
+
C,.,es,
20
.,/.
1 _ i+i-=~
1_j_+j_,.2,
Q,"' I0/3
R~"g~11..
y-
5
ID
\;
\2.. - 30
ID
\( ~ 101., -
.
2.0 GO
R_ =-
-~
___,I 1s.3~---
12 t 10
-3
=
15 I/:,
15 ·3
~ . \/o\-\me\er
\
read\oi
V= 12.ia 1.
\lV
=
v10, = RTh,Im
I=V~.Y_
Rio ,
_;_-
Riot
~10
"' l:.Q__
IOtW
11Vl
11v-
J_ :
Rn
'/,.
I<-
v
12,o t~io
V ,. 1 xl:l. : <ZV
o
J._ t J_
~ro
1000
RII B.1. ~
/,
.
~irchho~fs lo.ws (\JoHuae i currerrt)
charoe)
TI I= o
lurreJ~t Cconservcrhon
, 1=or ony June hon
2/>
t:,,><
A
=
,/.
-~ G A
]A
\
0~
?;A
1A
1A
X
1
l
o+2.
Il
!
1
'
=6 +-t
x.. - ~Al;
Vo\Jr°'%~
• \= or ony closed \oo~
TI£= z::: I
t
g__
\
£rr\-9-
Gornehmes [l.V==-0)
+o\on1 fue. current
-iaiYi~J
Ft
G) q5-=1~1-t-I3ixL\O+-I 1 K30
"5 6t p1- l\ -rr 7:,
~o +-~5 =- 11.'I- \
1
~1£
11v..20
· i1 11. t 1.\1 I, ?-.f1 '5 · 1
'3 9-uo1ions
i3
J..1 +I2..-;-l~==-O
u()knowns
:) T, ~-0.'3(i A ""1 1 =~.roA
( in o~ le. cl,ra,\-i(X))
0
I~ =i.lA
(1J
(-i,)
\Jea\ k non-id~\ me¼?rs
• \ n order ~r the me~rs
not -\-o 1r)ter~.ere..
resis4nnce h
in~ n; \e CiolroJ)
506
so no curren-1i+ fZ.eal!y ~ioHt
I
I
\
I
,
I
)
I
I I '
I
I
I
I /
I
I
I
I I I
I
I
Hi
rol(j
h
. CntJodute
• IJJe. ose °' -po-kntal divickr to
O\Jtr o... component.
1.0.r . resis\tlr)
\/Or~ the vo\+rtie.
E.rj. \JO\ume_ c..ontrol J Ii ~ht cl.immer
Problem
( co.n'+__ ~ e nhis c9r,f,)echon} · .
-
-
Hi" volto.3e:
,1
;'
1000 x llV %.I L~V
I
riv Hax
volta3e:
1060
i<.
11v = 12v
1000f-0
very \.imikJ~
(\,~'ti+ \<:. 'oriu"'t or
solu-hon
nv-
¼ink Ii ke this
I7
l
ver1
btft;
\l\1----'-"
0
-----. llV
----,-,
l
Ru
-1-hilll
~llY
1
1
~-.
2.
1k.
v
E lecnic. ce\\:,
5.
E"1+
cell
orio-
j_
,nren,a.l re sr;)ta.nce
E ::: em~ voltocf cJ-
-
l
.
o._
wnen ·no
source
corre(\ t
(adv~\\~ ~"I \JU)f
r= 'in\erno.\ · re.r:.i~tancP
.
= re.s,~tarice of the. eel\ ihe.J~
R. (increose..s as .it'~ ose.cl ")
1
cell
,-
-
r
I
f. 1
'··. I
I
_'.
conMt mea::iure.
/
dire_c:rly
E= Vp_-t'ilr
-= RI +rl
l_E T(IL•rl]
OLro~"::>
t'ne.:- re,si~-nr- == 1.~N . f.. = 1. 44V.
50Jl- v =1. 91 V
"J::, ijj_ ~o .02.ilA
{-,c__
50
t,i(i)@
r@Cs~lJ
w; vo\l-o.~e.
O\ICf
\Ire.
\oacl
r~?
~::.\JL+Yr
'I. 44 = t 41 .i. Vr
Yr =0.01\J
\/ =r i -7 r=
y_ . , o.o,
I
o oii2.
:di Jl.
~\a.Jll
fi,5JoJle
Power
.r=ri
I
en~roy ITUN,krreJ
TQ
I=~ ='>'1n time
lll
W=QV-=- Il)tV
=")
~J
\N= QV
1
cY)arcf move~ thmu0~
.
W =IV
Dt
~
2
Total pcwe( :
E.
'
Co.pO:c"1ty !::. obili+-~ ot
(of- °' eel\ )
tK
Q
lP=IV -1)=RI~=
R
I
J
tV" e. . c.o II du. C.-h:l I
Q=I6t
-=')
El(
g.:
I
°'
cell -\o l'ele~ cha~e..
Sa.rn~n
$8 30C0rflA'1
0
\Pnon~ '/. . :)..1-00 MAh
3oOO rr1Ah =1
con
su.pply
3000 (Y)A ~or 1h or
1rnA &r- 3'.:XOh or
')mA ~r 1500 h
( hve.. +o on ex ~f)t-)
for mos1
-4--__;_.~------:.......____;)
t,rne ('1'i r""I)
of life-time
\
Internal resistance graph - question
The graph to the left depicts the voltage across
the cell (or equally across the variable resistor)
as the variable resistance is increased.
Detemine:
a)
The emf of the cell
b)
The current in the external circuit when
the variable resistor is reduced to zero
c)
The internal resistance of the cell
0.10 0.20 0.10 G.-10 0-'0 0.60 0.70 0.M> 0..90
[ \¥::,·
·itzo l1a.1. !
+· •
@
E,_ ={.5V
@
I~ ti~
m, JIA t,.;, • .
tO
«i ?:@
U
1 l::i:+:
U
©
J,...
15
Ailernahve~
t,~I(ll+rJ
£~:r12+Ir
Choose
a.
·-1.S-= D.+ i +0.6 r ==1 r==- \.2~
1J
·~ .~ l:b
f 0 .,M
'
A ., corre(\t t?r:Golu.c.e.s,1 o.
. ~-\ru.iGht wire..
--:
]ErI
;
=
I
1
BL~
1@~er R ,~ l
I •
t
I
I
I
Force. on
cnarw~ r-r·hcle/current carr~i~ wire (L ~R)
0--
• curreo-\- coxr'f.11 '-lJire
-
I
•cha~ed po.rhc\e
-------:,/If----)
----,l!Hr--~B
]F~U~ sine
\F~ BQ~sine)o+
l
~loci½
oi
l.01~€..
F
di=B
r
• Force
on
rtll
-\1..uo
Fhd~
~:on
o~ +pa<tick.
(it - =?yever.se.. the.. Pi,rc.e..J
1
wire5.
\\rr
B-~eld c~led
~rce. ol\
ftf~\
IJ.\- v.,,re_ (LHRJ
~AKOOT
-1-eqevl f\,IQl\t-5
f-orce on two wires: (a »met or repel~)
''
'' ''
iI
I.
:r.
0)
t
'' '
0
two
wo..~s a~ -rhirikin
!-fl/RH rule
©
-)~ij~
~:
B-fielJ. c~o.lecl
)C
X
l
X
r
X
X.
f
\.\J\re.s os-e. 'voshe.J.. -le
II
the midcHe.
repel
X
B-~e.\J Cttctkd- by
r\~Y)t w·, re..
/
X
X.
" F
(
6~
d
X.
:
a¾rac+
F
by ldt wire.
®
I
'I
\A) \feS
o.wCL'-f
Qfe_ l~()~w I
+ne. m1ckJ.,le.
Th~ B-~e,\J
'o'f
- \ t'\ c. reo...~1 f'i
CO.fl
O tY\ e.
'oe.
\()(Jib.~
cu r re.!\ l .
- ·1()(, ell.~l('\i
.:\f
\Qof 5
- puttind a0 \ro()bar ·1nsi cle.
'
I
I
'
)(
)(
I
:
me.
r
k0-~ne.tic e.~\ect'S
5
or dectnc.
CJJrrents
helJ line0~ • north-'/ south
• more dense -") stwni{r helJ
never c.rncss
0
• H.°'~ne+ic., ~e\J ~rrend th (~ J
~5n~c t·e,\J Jue_
e
·,':) mea.sored
:tD correAts
Befol
current -pmcluces
Q
fare on
0-..
in
current coJT\j.!DC wire.
,(-,_
¥=BIL
1
:-1tF
1
• The.. wire will experience_
1m, an th•
w,re.
(111
mo..~"· ne
~~n~tl"I
=
)I
°' fu~e
..-=-
BI l sine
'$,
1
\
c.u rrefll
\en ~th o~ the
t.u'i'r-e,
2
teslo.. (T .. ~s A
1
~
Force
°' ch0-ro,,eJ.
-a
0'1
-----~
f-arncl e
Snt.()oth
JF=B~v~e\
force ordhe
--------11)
6haie
ru. Ie
1
tria~h .tielo1
.----c-1-I-----,
-~~vJ~~_e__
Left- - hanJ
f.
C.iive~
\
'--speecl oP +he cha~e
cra1 e (it c.urrent =drift speeJ)
.\-he olirecnon
o~
+he .-rcrc.e_)
Tht1.mb = Force_
.
1
\
in~e'.( =- Br ;(\elJ
.
i
1,( l
IY)\0<J It.~ cur reotl/tt-ho1.r·8e (+)
Nole.I fame in Of\10'::.i\e. Jiredioo tr C'\~o.fwe_ cha.ige__ 1. ·