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NORTHERN CAPE DEPARTMENT OF EDUCATION NOORD- KAAP DEPARTEMENT VAN ONDERWYS
PHYSICAL SCIENCES/ FISIESE WETENSKAPPE PHYSICS/FISIKA
Grade 11 /graad 11
ELECTRIC CIRCUITS
ELEKTRIESE STROOMBANE
memorandum
COMPILED BY/SAAMGESTEL DEUR: G. Izquierdo Rodriguez
2020
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PHYSICS/FISIKA
SOLUTIONS/OPLOSSINGS:
QUESTION 1/VRAAG 1 (2)
1.1 D (2)
1.2 B (2)
1.3 A (2)
1.4 D (2)
1.5 A (2)
1.6 D (2)
1.7 C (2)
1.8 C (2)
1.9 D (2)
1.10 D (2)
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QUESTION 2/VRAAG 2
2.1 The potential difference across a conductor is directly proportional to the
current in the conductor at constant temperature. Die potensiaalverskiloor 'n geleier is direkeweredigaan die stroom in die geleier by konstantetemperatuur.
(2)
2.2.1 𝑅 =
𝑉
𝐼
𝑅 =12
2
𝑅 = 6 𝛺
(3)
2.2.2 POSITIVE MARKING FROM QUESTIONS 2.2.1
POSITIEWE NASIE VANAF VRAE2.2.1 OPTION 1/OPSIE 1
RT = Rp + Rs
Rp =R1×R2R1+R2
Rp =4 × 44 + 4
Rs = 6 − 2
Rs = 4 Ω
V = IR
V = 2 × 4
V = 8 V
OPTION 2/OPSIE2
𝑅𝑇 = 𝑅𝑝 + 𝑅𝑠
1
Pp= 1
R1+ 1
R2
1Pp
=14
+14
𝑅𝑝 = 2 Ω
Any one/Enige een
Any one/Enige een
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6 = 2 + Rs
V = IR
V = 2 × 4
V = 8 V OPTION 3/OPSIE 3
Rp =R1×R2R1+R2
Rp =4 × 44 + 4
𝑅𝑝 = 2 Ω
Vp = IRp
V = 2 × 2
V = 4 V 𝑉 = 𝜀 − 𝑉𝑝
𝑉 = 12 − 4
V = 8 V
(6)
2.3.1 INCREASES/TOENEEM
Total resistance decreases,emf is constant and total current is inversely proportional to resistance. Totale weerstand afneem, emf is konstant en totale stroom is omgekeerd eweredig aan weerstand.
(4)
2.3.2 INCREASES/ TOENEEM
Total current increases, resistance is constant and potential difference is directly proportional to current. Totale stroom neem toe, weerstand is konstant en potensiaalverskil is direk eweredig aan stroom.
(4)
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Any one/Enige een
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QUESTION 3/VRAAG 3
3.1 The potential difference across a conductor is directly proportional to the current in the conductor at constant temperature. Die potensiaalverskil oor 'n geleier is direk eweredig aan die stroom in die geleier by konstante temperatuur.
(2)
3.2 Option 1/Opsie 1
321
1111
RRRRparallel
6
1
6
1
6
11
parallelR
Rparallel= 2 Ω
Requivalent/total= Rparallel + Rseries
Requivalent/total= 2 + 3
Requivalent/total= 5 Ω
R
VI
5
12I
AI 4.2
Option 2/Opsie 2
Requivalent/total= Rparallel + Rseries
R1= R2= R3= R
Requivalent/total= n
R+ Rseries
Requivalent/total= 3
6 + 3
Requivalent/total= 5 Ω
R
VI
(either one/enigeen)
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5
12I
AI 4.2 (6)
3.3 Increases/ Vermeerder
Potential difference (Voltage)/emf remais constant (is the same) and total resistance
decreases.
Potensiaalverskil /emk bly konstant (is dieselfde) en totale weerstand neem af (3)
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QUESTION 4/VRAAG 4
4.1 Rt= R1+ R23
R23=32
11
RR =
2
1
2
1 =
2
2= 1Ω
Rt= 4 +1= 5 Ω
(4)
4.2 OPTION N1/OPSIE 1
Ammeter 1
I=TR
V=
5
12 = 2.4 A
Ammeter 2
I= I2+I3
I2=I3
I2= 2
4,2= 1,2 A
OPTION 2/OPSIE 2
V23= ε – V1 = 12 – (2,4X4) = 2.4 V
I= 2
4,2= 1.2 A
(4)
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OPTION 3/OPSIE 3
V1= IR1= 2.4 x 4 = 9,6 V
V23= ε – V1 = 12 – 9,6 = 2.4 V
I= 2
4,2= 1.2 A
4.3 OPTION 1/OPSIE 1
RIP 2
4)4.2( 2P
04.23P W
OPTION2/OPSIE 2
P= IV
P=I(ε-I2R2)
P=2.4 [12-(1,2 x 2)]
P=23.04 W
(3)
4.4 Yes/Ja
Resistance in the circuit increases /Weerstand in die stroomban vermeerder
Current decreases/Stroom verminder
For a constant resistance power is directly proportional to the square root of current
(P α I2/Vir ‘n konstante weerstand, is drywing direk eweredig aan die kwadraat van
stroom (P α I2)
(4)
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QUESTION 5/VRAAG 5
5.1.1 OPTION 1/OPSIE1
21
111
RRRP OR/OF
4
1
2
1
33,1PR
TR = 1 ,33+3
=4,33
OPTION 2/ OPSIE 2
Rp = 21
21
RR
RR
=42
42
x = 1,33Ω
TR = 1 ,33+3
=4,33
(5)
5.1.2 POSITIVE MARKING FROM 5.1/ POSITIEWE NASIEN VANAF 5.1
I
VR
4,33 = I
12
I = 2,77 A
(4)
5.1.3 POSITIVE MARKING FROM 5.1.2/ POSITIEWE NASIEN VANAF 5.1.2
V3Ω =IR OR V// = I T R//
=2,77 x3 = 8,31 V = 2,77 x 1,33
V = 12-8,31 = 3,69 V V// = 3,68 V
(4)
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5.2 Decreases The total resistance increases. According to I =
R
V, when R
increases I decreases as potential difference is constant.
Afneem. Die totale weerstand neem toe Na aanleiding van I =R
V,
wanneer R toeneem sal I afneem.
(3)
5.3.1 ANY TWO/ ENIGE TWEE
Temperature/ Temperatuur
Length/Lengte
Cross sectional area(thickness) of material/ Dikte (deursnee) van die
materiaal
(2)
5.3.2. Conductor Q / Geleier Q
Option 1/Opsie 1
For the same potential difference, wire Q has a higher current than
wire P. Therefore wire Q has a lower resistance than wire P.
Vir dieselfde potensiaalverskil het draad Q ‘n hoër stroom as draad P.
Daarom het draad Q ‘n laer weerstand as draad P.
Option 2/Opsie 2
The gradient of the graph for wire Q is bigger than that of wire P.
Gradient =V
1 is bigger, thus R
I
V is smaller.
Die gradient van die grafiek vir draad Q is groter as die van draad P.
Gradient =V
1 is groter, daarom R
I
V is kleiner.
(3)
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QUESTION 6/VRAAG 6
6.1 The potential difference across a conductor is directly proportional to the current in the conductor at constant temperature. Die potensiaalverskil oor 'n geleier is direk eweredig aan die stroom in die geleier by konstante temperatuur.
(2)
6.2.1 V= IR OR/OF R =
I
V
R = A
V
2
12
R = 6 Ω
(3)
6. 2.2 POSITIVE MARKING FROM 6.2.1 /POSITIEWE NASIEN VANAF 6.2.1
RT = Rx + RAB OR/OF Rx = Rt - RAB
BA RR
11
R
1
AB
OR/OF BA
BA
RR
RRR
2
1
3
1
R
1
AB
OR/OF 23
23
R
Rparallel= 1,2 Ω
R= 6- 1,2
R= 4,8 Ω
(4)
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6.2.3 POSITIVE MARKING FROM 6.2.2 /POSITIEWE NASIEN VANAF 6.2.2 OPTION 1/OPSIE 1
VAB = I R
VAB = 2 x 1,2
VAB = 2,4 V
IA =R
VAB
IA =3
4,2
IA = 0,8 A
OPTION 2/OPSIE 2
IAB= IA + IB
BBAA RIRI 23 BA II
AA II2
32
IA = 0,8 A
(3)
6.3 OPTION 1/OPSIE 1
RIP 2
8,422 P
WP 2,19
OPTION 2/OPSIE 2
IVP
IRV
8,42V
VV 6,9
6,92P
(3)
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WP 2,19
OPTION 2/OPSIE 2
R
VP
2
ABVV
2,1212 V =
VV 6,9
8,4
)6,9( 2P
WP 2,19
6.4 DECREASES/ VERMINDER
Total resistance increases emf/ Terminal voltage/terminal potential
difference is constant current decreases.
Totale weerstand verhoog emk / terminaalpotensiaalverskil / terminale
potensiaalverskil konstant stroom afneem.
OR/OF
Total resistance increases and current is inversely proportional to
resistance when emf/terminal voltage/terminal potential difference is
constant.
Totale weerstand verhoog en stroom is omgekeerd eweredig aan weerstand
wanneer emk / klemspanning / terminale potensiaalverskil konstante is.
(3)
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QUESTION 7 / VRAAG 7
7.1
21
111
RRRparallel
12
1
4
11
Rparallel
Rparallel = 3 Ω
(3)
7.2 V// = IR//
= (2)(3)
= 6 V
(3)
7.3 I4Ω = V//
R
= 6
4
= 1,5 A
(3)
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7.4
tR
VE
2
6012
)6( 2E
E = 180 J
OR/OF OR / OF
I12 = V/R E = IVt
= 6/12
= 0,5 A = (0,5)(6)(60)
E = I2Rt
= (0,5)2(12)(60) = 180 J
= 180 J
(3)
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QUESTION 8/ VRAAG 8
8.1 Current / Stroom (2)
8.2
8.2.1 (4,0 : 0,64) (2)
8.2.2 Temperature was not kept constant / Die temperatuur is nie konstant gehou
nie.
(2)
8.3 Gradient / Gradiënt =
04
064,0
= 0,16
R= 16,0
1 = 6,25 Ω
(4)
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QUESTION 9/VRAAG 9
9.1. What is the relationship between potential difference and current in a circuit with a resistor
with constant resistance?
Wat is die verband tussen die potensiaalverskil en die elektriese stroom in ‘n stroombaan met ‘n weerstand met ‘n konstante weestand? (2) 9.2. When current increases potential difference also increases.
Wanneer die stroom verhoog, verhoog die potensiaalverskil ook as die weerstand konstant bly. (2)
9.3. 9.3.1 Potential difference/ Potensiaalverskil
9.3.2 Current /Stroom (2)
9.4.
1mark straight line (shape)
1 mark both axes lables and unit
1 mark both axes scale
1 mark for estarting at 0.02 (4)
9.5 Gradient/ Gradiënt = I
V
Gradient/ Gradiënt = 02,008,0
624
Gradient/ Gradiënt = 300 (3)
9.6. Resistance of the resistor/ Weerstand van die resistor.. (1)
9.7. The hypothesis is correct the potential difference is directly proportional to current when
the resistant is constant.
Die hipotese is korrek, want die potensiaalverskil is direk eweredig aan die sterkte van die elektriese stroom wanneer die weerstand van die resistor konstant gehou word. (2)
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