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MODUL • Fizik TINGKATAN 5

Memahami teori melalui pendekatan matematik: / Understanding the theory through the mathematical approach:
V [malar / constant]
I [#] = R [$]
V adalah malar / V is constant
I bergantung pada R / I depends on R
R semakin berkurang, I semakin bertambah atau sebaliknya / As R decreases, I increases or vice versa
I berkadar songsang dengan R / I is inversely proportional to R
I α 1
R
Untuk kombinasi sambungan beberapa buah perintang atau alat elektrik, R = rintangan berkesan
Maklumat tambahan:
For combinations of several connection or electrical resistors, R = effective resistance Additional information:
Pemboleh ubah / Variables :
Dimanipulasikan / Manipulated : Rintangan berkesan, R / Effective resistance, R
Bergerak balas / Responding : Jumlah arus di dalam litar, I / Amount of current in circuit, I.
Dimalarkan / Constant : Beza keupayaan, V / Potential difference, V.

Daya Gerak Elektrik dan Rintangan Dalam
2.4 Electromotive Force and Internal Resistance

Perbandingan antara daya gerak elektrik dan beza keupayaan UNIT 2
Comparison between electromotive force and potential difference
UNIT 2
D.g.e. (Daya gerak elektrik) Beza keupayaan
E.m.f. (Electromotive force) Potential difference

Bacaan voltmeter = d.g.e. = E Bacaan voltmeter = V
The reading of the voltmeter = e.m.f. = E The reading of the voltmeter = V
V V
1.5 V
Sel kering
Dry cell

Sel kering
Dry cell Arus mengalir
Tiada arus mengalir Current flowing
No current flow
V < E
• Dalam litar terbuka , tiada arus yang mengalir. • Dalam litar tertutup, terdapat arus yang mengalir. Beza
Beza keupayaan yang merentasi sel ialah nilai keupayaan yang melalui sel adalah lebih kecil
daya gerak elektrik (d.g.e) . daripada daya gerak elektrik (d.g.e) sel.

In the open circuit, there is no current flow. In a closed circuit, there is a current flows. The potential
The potential difference, V, across the cell is equal to the difference, V, across the cell is smaller than the e.m.f. of
electromotive force (e.m.f.) . the cell.
• Susutan dalam beza keupayaan merentasi sel ini disebabkan
• Bacaan voltmeter ialah 1.5 V. oleh rintangan dalam sel.
The voltmeter reading is 1.5 V. This drop in potential difference across the cell is caused by the
internal resistance of the cell.
• Daya gerak elektrik adalah sama dengan bacaan voltmeter
yang disambungkan terus melalui terminal sel dalam litar • Jika bacaan voltmeter ialah 1.2 V, beza keupayaan yang
terbuka. merentasi lampu ialah 1.2 V.
The e.m.f. is equal to the reading of the voltmeter which is If the voltmeter reading is 1.2 V, the potential difference across the
connected directly across the terminal of the cell in an open lamp = 1.2 V.
circuit.

• Daya gerak elektrik (d.g.e.) = 1.5 V • V < E
Electromotive force (e.m.f.) = 1.5 V

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