EMF, induction & motors

V = ε − Ir; induction needs CHANGE; F = BIL left-hand rule. Exam-style ε = 9.0 V, r = 0.50 Ω, R = 5.5 Ω Terminal voltage? I = ε/(R + r) = 9.0/6.0 = 1.5 A Lost volts = Ir = 0.75 V V = 9.0 − 0.75 = 8.25 V ✓ ≈ 8.3 V — what a voltmeter across the battery reads.

Magnetism toolkit

Wire: right-hand grip. Solenoid: thumb = N pole.
Motor effect: F = BIL, left-hand rule (F-B-I).
Induction: field must CHANGE (Faraday); induced current opposes the change (Lenz).
Transformer: Vs/Vp = Ns/Np — AC only.

Practice for this standard covers the whole topic — flashcards and quiz.