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MODUL • Fizik TINGKATAN 5

4 Sebuah akumulator menghasilkan arus 4 A apabila ia disambungkan ke perintang 2 Ω. Apabila akumulator yang
sama disambungkan ke perintang 3 Ω, ia menghasilkan arus 3 A. Tentukan daya gerak elektrik dan rintangan dalam bagi
akumulator itu.
KBAT An accumulator produces a current of 4 A when it is connected to a 2 Ω resistor. When the same accumulator is connected to a 3 Ω
resistor, the current produced is 3 A. Determine the electromotive force and the internal resistance of the accumulator.
Penyelesaian
Solution
Apabila akumulator disambungkan kepada perintang 2 Ω, Persamaan (i) = Persamaan (ii),
When the accumulator is connected to the 2 Ω resistor, Equation (i) = Equation (ii),
E = V + Ir 8 V + (4 A)r = 9 V + (3 A)r
= IR + Ir r A = 1 V
= (4 A)(2 Ω) + (4 A)r 1 V
E = 8 V + (4 A)r (i) r = A
. . r . = 1 Ω

Apabila akumulator disambungkan kepada perintang 3 Ω, Dari (i), / From (i),
When the accumulator is connected to the 3 Ω resistor, E = 8 V + (4 A)(1 Ω)
E = V + Ir = IR + Ir = 12 V
= (3 A)(3 Ω) + (3 A)r
.
E = 9 V + (3 A)r (ii) . . UNIT 2
e.m.f. = 12 V
UNIT 2

5 Satu eksperimen dijalankan untuk menentukan daya gerak elektrik, E dan rintangan dalam, r, pada sel kering.
An experiment is carried out to determine the electromotive force, E, and the internal resistance, r, of a dry cell.

KBAT
V / V

1.5

1.0

0.5

I / A
0 0.2 0.4 0.6 0.8 1.0 1.2

Tentukan / Determine
(a) Berdasarkan graf di atas, / Based on the graph above,
(i) apakah yang berlaku apabila I meningkat? / what happens when I increases?
(ii) tentukan nilai beza keupayaan, V, apabila arus, I = 0.0 A. Tunjukkan pada graf, bagaimana anda menentukan nilai V.
determine the value of the potential difference, V, when the current, I = 0.0 A. Show on the graph, how you determine V.
(iii) namakan kuantiti fizik yang ditunjukkan oleh (a)(ii). / name the physical quantity that is shown in (a)(ii).
(b) Diberi rintangan dalam, r, pada sel kering ialah r = –m, di mana m ialah kecerunan bagi graf. Kirakan nilai r.
The internal resistance, r, of the dry cell is given by r = –m, where m is the gradient of the graph. Calculate the value of r.
(c) (i) Daripada graf, nyatakan nilai V, apabila I = 0.80 A. Tunjukkan pada graf, bagaimana anda menentukan nilai V.
From the graph, state the value of V, when I = 0.80 A. Show on the graph how you determine the value of V.

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