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 define electric potential as potential energy per unit charge, and potential difference as the change in it. (Guide: “From potential energy to potential”)
- I can explain why V can be zero where E is not, and the reverse. (Practice Q1, Q6)
- I can explain how a battery keeps a potential difference between its terminals. (Guide: “Batteries”)
- I can explain why equipotentials cross field lines at right angles and why no work is done along one. (Guide: “Equipotential maps”)
Calculation and skills
- I can find V for several point charges by adding scalar terms with their signs. (Guide: Worked example 1; Practice Q5)
- I can integrate k dq/r for a ring on its axis, an arc at its centre and a finite rod on its line or perpendicular bisector. (Guide: Worked example 2; Practice Q2, Q6)
- I can find a potential difference near a long wire or cylinder using ΔV = −∫E·dl. (Guide: Worked example 3; Practice Q7)
- I can find E_x from V(x) using E_x = −dV/dx. (Practice Q4, Q6)
- I can use ΔU = qΔV to find the work needed to move a charge. (Practice Q5)
- I can plot V against position with scaled, labelled axes. (Practice Q6)
Reasoning
- I can estimate field strength and direction from the spacing and values of equipotentials. (Guide: Figure 1; Practice Q3)
- I can decide which of two points is at higher potential from the direction of E. (Practice Q7)
- I can explain why V cannot be referenced to infinity for an infinite line of charge. (Practice Q7)
All ticked? Move on to Topic 9.3, Conservation of Electric Energy, or return to the course roadmap.