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 explain how the field of a moving charge depends on its velocity and on the distance and direction to the point. (Guide: “A moving charge makes a magnetic field”; Practice Q2)
- I can say where the field of a moving charge is greatest and where it is zero, and sketch its direction above and below the line of motion. (Guide: Figure 1; Practice Q4)
- I can explain why a magnetic force does no work and so cannot change a particle’s speed. (Guide: “The magnetic force does no work”; Practice Q5)
- I can explain how a Hall potential difference forms and why it reveals the sign of the carriers. (Guide: “The Hall effect”; Practice Q7)
Calculation and skills
- I can calculate the field vector of a moving point charge using B = (μ₀/4π) q(v × r̂)/r². (Guide: Worked example 1; Practice Q4)
- I can find the direction of F = q(v × B) with unit vectors or the right-hand rule, reversing it for negative charges. (Practice Q1, Q5)
- I can derive and use r = mv/(qB) and T = 2πm/(qB), and find the radius and pitch of a helix. (Guide: Worked example 2; Practice Q5)
- I can derive the condition v = E/B for a charge to pass undeflected through crossed fields. (Practice Q6)
- I can derive ΔV_H = IB/(nqt) and use it to find a drift speed, a Hall potential difference or a carrier density. (Guide: Worked example 3; Practice Q7)
- I can plot experimental data with labelled axes and use the gradient of the best-fit line. (Practice Q7)
Reasoning
- I can predict factors of change, such as how the radius changes when the accelerating potential difference changes. (Practice Q3, Q6)
- I can decide which way a particle is deflected when the electric and magnetic forces do not balance. (Practice Q6)
- I can plan a procedure that controls variables and checks for errors in a magnetic-field experiment. (Practice Q7)
All ticked? Move on to Topic 12.3, Magnetic Fields of Current-Carrying Wires and the Biot–Savart Law, or return to the course roadmap.