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MODUL • Fizik TINGKATAN 5

Daya gerak elektrik (d.g.e) / Electromotive Force (e.m.f)
Jumlah tenaga elektrik yang dibekalkan kepada satu coulomb cas yang mengalir melalui sel.
Simbolnya ialah E. Unitnya ialah V.
The total electrical energy given to one coulomb of charge flowing through the cell.
The symbol is E. The unit is V.

Rintangan dalam, r / Internal resistance, r Beza keupayaan, V
Rintangan dalam sel disebabkan oleh rintangan bahan kimia di dalam sel. Potential difference, V
The internal resistance of a cell is due to the resistance of the chemicals in the cell.

Ia menyebabkan / It causes

• "Kehilangan" tenaga haba dalam sel. Beza keupayaan Beza keupayaan
"Loss" of heat energy in the cell. merentasi sel Beza keupayaan merentasi
apabila tiada merentasi rintangan dalam
• Beza keupayaan yang merentasi terminal adalah arus mengalir = rintangan luar + Potential UNIT 2
kurang daripada d.g.e. Potential Potential difference
UNIT 2
difference across
Potential difference across the terminals of the cell to be difference across external resistance across internal
cell when no
less than the e.m.f. current flows V resistance
Ir
E
E = V + Ir atau / or E = IR + Ir

Rintangan dalam, r, boleh ditentukan
daripada kecerunan graf Kecerunan graf yang
E – V = Beza keupayaan yang V / V The internal resistance, r can be negatif menunjukkan V

hilang, gradient sentiasa kurang daripada E
Oleh itu, kehilangan beza determined from the disebabkan oleh nilai Ir.
keupayaan = Ir. Kehilangan E of the graph The gradient of the graph
beza keupayaan disebabkan oleh is negative showing that V

rintangan dalam. is always less than E by the
E – V = Potential drop, E – V value of Ir.
Hence, potential difference drop = Ir.
Drop in potential difference is due to
internal resistance. V
I / A
0

Graf menunjukkan garis lurus. Garis lurus boleh dijelaskan oleh persamaan:
The graph shows a straight line. The straight line can be represented by the equation:

V = –r I + E

Jika garis lurus diekstrapolasikan sehingga ia menemui paksi tegak, V, nilai I = 0 dan V = E diperoleh. Ini menunjukkan apabila
tiada cas yang mengalir, beza keupayaan yang melalui sel ialah daya gerak elektrik.
If the straight line is extrapolated until it meets the vertical axis V, the values of I = 0 and V = E are obtained. This shows that when no
charges flow, the potential difference across the cell is the electromotive force (E).

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