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 power as the rate of energy transfer and explain why 1 A × 1 V = 1 W. (Guide: “Power as a rate of energy transfer”)
- I can describe where energy enters a circuit, where it leaves and where it can be stored. (Guide: “Energy into, out of and within a circuit”)
- I can explain that a bulb’s brightness increases with its power, and that a rating applies only at the stated ΔV. (Guide: “Bulb brightness”; Worked example 2)
Calculation and skills
- I can derive P = IΔV from ΔE = qΔV and I = q/Δt. (Guide: “Deriving P = IΔV”)
- I can derive P = I²R and P = ΔV²/R using Ohm’s law. (Guide: “Two forms for a resistor”)
- I can calculate power and energy with correct unit prefixes and time in seconds. (Guide: Worked example 1; Practice Q1, Q5)
- I can predict the factor by which power changes when I, ΔV or R changes. (Practice Q2, Q5d)
- I can derive a symbolic expression for the power of a wire in terms of ρ, L, d and ΔV. (Guide: Worked example 3; Practice Q7a)
- I can sketch P against I, and P against R at fixed ΔV and at fixed I. (Guide: Figure 1; Practice Q6)
Reasoning
- I can compare the brightness of bulbs that share the same ΔV, or the same current, and justify which is brighter. (Practice Q3, Q4)
- I can show that energy is conserved by comparing the power from the battery with the total power dissipated. (Guide: Worked example 2; Practice Q7c)
- I can evaluate a claim such as “larger resistance always means more power”. (Practice Q6c)
All ticked? Move on to Topic 11.5, Compound Direct Current (DC) Circuits, or return to the course roadmap.