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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

1


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)

[20]

2


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

3


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)

[19]

Any one/Enige een

4


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)

5


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)

[11]

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)

[15]

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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)

[21]

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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)

10


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)

11


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)

[18]

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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)

13


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)

[12]

14


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)

[10]

15


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)

[16]

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