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MODUL • Fizik TINGKATAN 5

Latihan / Exercise
1 Tentukan rintangan berkesan merentasi PQ bagi setiap litar berikut:
Determine the effective resistance across PQ for each of the following circuits:
(a) 20 Ω 10 Ω 5 Ω (c) 8 Ω
P Q 10 Ω 20 Ω
P Y 8 Ω Q
KBAT
(b) 8 Ω (d) 8 Ω 8 Ω
8 Ω 8 Ω
KBAT
P 8 Ω Q P 4 Ω 4 Ω Q
Penyelesaian / Solution

(a) R = 20 Ω + 10 Ω + 5 Ω (c) 1 1 1 (d) 1 1 1 1
PQ = + = + +
= 35 Ω R YQ 8 Ω 8 Ω R PQ 16 Ω 8 Ω 8 Ω
1 2 1 1 + 2 + 2
(b) 1 1 1 1 R = 8 Ω R = 16 Ω
= + + YQ PQ
R PQ 8 Ω 8 Ω 8 Ω 1 5
1 3 \ R = 4 Ω = UNIT 2
YQ
= R PQ 16 Ω
R PQ 8 Ω \ R = 10 Ω + 20 Ω + R 16 Ω
UNIT 2
8 Ω PQ YQ \ R =
\ R = = 10 Ω + 20 Ω + 4 Ω PQ 5
PQ 3 = 34 Ω = 3.2 Ω
= 2.67 Ω
2 Tentukan bacaan ammeter bagi litar berikut apabila suis dihidupkan.
Determine the ammeter reading for following circuit when the switch is turned on.
(a) 8 Ω (b) (c)
KBAT 4.5 V 24 V
X 8 Ω Y Z S S
8 Ω
2 Ω 6 Ω
A 8 Ω A R2 8 Ω I2 A 2.5 Ω
R1 2 Ω 2 Ω
S X Y R3 Z U X Y Z
Penyelesaian 20 V I3
Solution
I 2 Ω
(a) V = IR XZ (b) V = I R XZ 2 A
XZ
XZ
XZ
1 = 1 + 1 1 = 1 + 1 I R 2
R YZ 8 Ω 8 Ω R YZ 2 Ω 2 Ω Y 2 Ω Z
1 2 1 2
= = I
R YZ 8 Ω R YZ 2 Ω 3 R 3
\ R = 4 Ω \ R = 1 Ω
YZ YZ Dari bahagian litar yang merentasi YZ,
\ R = R + R \ R = R + R From the section of the circuit across YZ,
XZ XY YZ XZ XY YZ
= 8 Ω + 4 Ω = 8 Ω + 1 Ω I = I XZ
= 12 Ω = 9 Ω = 0.5 A

\ I = V \ I = V XZ Tetapi / But
R XZ XZ R
20 V XZ I = I 3
2
= 12 Ω = 4.5 V (Kerana R = R )
9 Ω
3
2
= 1.67 A = 0.5 A \ 2 I = I
2
2 I = 0.5 A
2
I = 0.25 A
2
\ Bacaan ammeter
Ammeter reading = 0.25 A
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