Electromotive Force And Ohms Law Current And Electricity
Electromotive force (emf):

Energy supplied per unit charge to maintain current flow.

Potential difference across terminals with no current draw.

Unit: Volts (V).
Ohm’s Law:

Current through a conductor is directly proportional to potential difference, assuming constant temperature and physical factors.

V = IR, where V is potential difference, I is current, and R is resistance.
Resistance:

Opposition to current flow in a circuit.

Unit: Ohm (Ω).

Affected by material, length, crosssectional area, and temperature.
Factors Affecting Current:

Potential difference.

Resistance.

Temperature.

Nature of the conductor.

Length of the conductor.

Crosssectional area of the conductor.
Kirchhoff’s Laws:

Current Law (KCL): Sum of currents entering a junction equals the sum of currents leaving the same junction.

Voltage Law (KVL): Sum of potential differences around a closed loop equals zero.
Electrical power:

Rate at which electrical energy is transferred or consumed in a circuit.

P = VI, where P is power, V is potential difference, and I is current.

Unit: Watt (W).
Energy Consumption in an Electric Circuit:

Energy consumed by a device is the product of power and operating time.

E = Pt, where E is energy consumed, P is power, and t is time.

Unit: Joule (J).