Electric Power, Energy, and Potential

Study Notes

Electric power (P) is the rate at which electric energy is transferred or converted
Unit: watt (W)
Formula: P = ΔW / Δt
Electric energy (ΔW) is the total energy transferred or converted
Unit: joule (J)
Formula: ΔW = V × I × t

Electric potential (V) is the potential difference between two points in a circuit
Unit: volt (V)
Also known as voltage or electromotive force (EMF)
Formula: V = W / Q
Electric potential difference is the work done per unit charge in moving a charge between two points

A circuit consists of a closed path through which electric current flows
Components: source of EMF, conductors, resistors, and loads
Types of circuits:
- Series circuit: components connected one after the other
- Parallel circuit: components connected between the same two points
- Series-parallel circuit: combination of series and parallel connections

Resistance (R) is the opposition to the flow of electric current
Unit: ohm (Ω)
Formula: R = V / I
Ohm's Law: V = I × R
Resistivity (ρ) is the resistance of a material per unit length and unit cross-sectional area
Formula: ρ = R × A / L

Electric power is the rate of electric energy transfer or conversion, measured in watts (W).
Electric power formula: P = ΔW / Δt, where P is power, ΔW is energy, and Δt is time.
Electric energy is the total energy transferred or converted, measured in joules (J).
Electric energy formula: ΔW = V × I × t, where V is voltage, I is current, and t is time.

Electric potential, also known as voltage or electromotive force (EMF), is the potential difference between two points in a circuit, measured in volts (V).
Electric potential formula: V = W / Q, where V is voltage, W is work, and Q is charge.
Electric potential difference is the work done per unit charge in moving a charge between two points.

A circuit consists of a closed path through which electric current flows, comprising a source of EMF, conductors, resistors, and loads.
Series circuit: components connected one after the other, with the same current flowing through each component.
Parallel circuit: components connected between the same two points, with each component having the same voltage.
Series-parallel circuit: a combination of series and parallel connections.

Resistance is the opposition to the flow of electric current, measured in ohms (Ω).
Resistance formula: R = V / I, where R is resistance, V is voltage, and I is current.
Ohm's Law: V = I × R, which relates voltage, current, and resistance.
Resistivity is the resistance of a material per unit length and unit cross-sectional area, measured in ohm-meters (Ωm).
Resistivity formula: ρ = R × A / L, where ρ is resistivity, R is resistance, A is cross-sectional area, and L is length.

Electric current is the flow of electric charge, measured in amperes (A).
Electric current formula: I = ΔQ / Δt, where I is current, ΔQ is charge, and Δt is time.
Voltage is the potential difference between two points in a circuit, measured in volts (V).
Voltage and current are related by Ohm's Law: V = I × R.