15–25% of the AP exam. Key topics: Current density, drift velocity, and resistivity (ρ), Resistance: R = ρL/A; Ohm's Law: V = IR, Power dissipation: P = IV = I²R = V²/R, EMF sources, terminal voltage, and internal resistance, Kirchhoff's Voltage Law (KVL) and Kirchhoff's Current Law (KCL), Series and parallel resistor networks: equivalent resistance, RC circuits: charging q(t) = Q_max(1 – e^(–t/RC)) and discharging q(t) = Q₀e^(–t/RC); time constant τ = RC, RL circuits: current build-up and decay; time constant τ = L/R, Initial and final conditions: capacitor as wire (t = 0, uncharged) or open circuit (t → ∞); inductor as open circuit (t = 0, no current) or wire (t → ∞).
Study guide content for this unit is being prepared. Check back soon for complete lesson notes, formula sheets, and worked examples.
