Electromotive Force And Ohms Law Current And Electricity
Electromotive force (emf):
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Energy supplied per unit charge to maintain current flow.
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Potential difference across terminals with no current draw.
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Unit: Volts (V).
Ohm’s Law:
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Current through a conductor is directly proportional to potential difference, assuming constant temperature and physical factors.
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V = IR, where V is potential difference, I is current, and R is resistance.
Resistance:
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Opposition to current flow in a circuit.
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Unit: Ohm (Ω).
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Affected by material, length, cross-sectional area, and temperature.
Factors Affecting Current:
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Potential difference.
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Resistance.
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Temperature.
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Nature of the conductor.
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Length of the conductor.
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Cross-sectional area of the conductor.
Kirchhoff’s Laws:
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Current Law (KCL): Sum of currents entering a junction equals the sum of currents leaving the same junction.
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Voltage Law (KVL): Sum of potential differences around a closed loop equals zero.
Electrical power:
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Rate at which electrical energy is transferred or consumed in a circuit.
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P = VI, where P is power, V is potential difference, and I is current.
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Unit: Watt (W).
Energy Consumption in an Electric Circuit:
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Energy consumed by a device is the product of power and operating time.
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E = Pt, where E is energy consumed, P is power, and t is time.
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Unit: Joule (J).
