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 a parallel-plate capacitor as two conducting plates holding equal and opposite charges, and say what Q means. (Guide: “Two plates, equal and opposite charge”; Practice Q1)
- I can explain why capacitance depends only on A, d and κ, and not on Q or ΔV. (Guide: “What sets the capacitance”)
- I can explain why the field between the plates is uniform and which way it points. (Guide: “The field between the plates”; Figure 1)
- I can explain the stored energy as the work done to separate the charge, and show it as an area on a Q–ΔV graph. (Guide: Figure 2; Practice Q4)
- I can explain how a dielectric reduces the net field and so increases the capacitance. (Guide: “Dielectrics”; Practice Q3)
Calculation and skills
- I can use C = Q/ΔV and C = κε₀A/d, converting mm and pF correctly. (Guide: Worked example 1; Practice Q1, Q5)
- I can find the field from E = ΔV/d or E = Q/(ε₀A) and the energy from U_C = ½QΔV. (Guide: Worked example 1; Practice Q4, Q5c)
- I can find the deflection of a charged particle between the plates using projectile-style equations. (Guide: Worked example 3; Practice Q6)
- I can plan an experiment to test C ∝ 1/d and find ε₀ from the gradient of a linear graph. (Practice Q7)
Reasoning
- I can decide whether Q or ΔV is fixed and predict how C, Q, ΔV, E and U_C change. (Guide: Worked example 2; Practice Q2, Q3)
- I can use a proportionality argument to predict whether a deflected particle hits a plate. (Practice Q6d)
- I can suggest why real capacitance data do not pass exactly through the origin. (Practice Q7d)
All ticked? Move on to Topic 10.7, Conservation of Electric Energy, or return to the course roadmap.