Work through the list without notes. If you cannot do a statement, follow its link, then come back. Guide = study guide; Practice = practice questions.
Understanding
- I can describe one cycle of an LC circuit in terms of where the energy is stored at each quarter-period. (Guide: “The idea: energy passed back and forth”; Practice Q6(d))
- I can explain why the current keeps flowing after the capacitor is empty. (Guide: “The idea: energy passed back and forth”)
- I can explain why the charge and current are a quarter-cycle out of step, and what that means for the inductor voltage at maximum current. (Guide: Figure 1; Practice Q2)
- I can state the mass–spring analogy: q with x, I with v, L with m and 1/C with k. (Guide: “The loop rule gives simple harmonic motion”)
Calculation and skills
- I can use energy conservation to find I_max from Q₀, or Q_max from a starting current. (Guide: Worked example 1; Practice Q4, Q7)
- I can apply the loop rule to get d²q/dt² = −q/(LC) and derive ω = 1/√(LC). (Practice Q6)
- I can calculate ω, f and T, keeping ω and f distinct. (Practice Q1)
- I can find the charge and current at a stated point in the cycle, such as when the energies are equal. (Guide: Worked example 2; Practice Q4, Q6)
- I can draw quantitative graphs of q, I and the energies against time with numbered scales and units. (Guide: Figure 1; Practice Q6(d), Q7(e))
Reasoning
- I can predict factors of change in T, I_max and energy, stating whether charge or voltage is held fixed. (Guide: Worked example 2; Practice Q3)
- I can plan an experiment to test T = 2π√(LC) and find L from a graph of T² against C. (Guide: “Designing an experiment”; Practice Q5)
- I can explain why a capacitor in an LC circuit can reach a voltage far larger than the battery that first supplied the energy. (Practice Q7(f))
- I can explain why a real LC oscillation dies away. (Practice Q5(d))
All ticked? This is the last topic of the course. Look back at Topic 13.5, LR circuits, or return to the course roadmap to plan your review.