Why does an alternating current in a primary coil induce a voltage in an adjacent secondary coil wound around a ferromagnetic core?
Answer and explanation
Correct answer: B. Mutual inductance: changing primary current produces changing magnetic flux linked to the secondary
- Step 1: An AC current in the primary produces an oscillating magnetic flux in the ferromagnetic core. Step 2. By Faraday's law, this changing flux links with the secondary coil, inducing an emf: V_s = -N_s d(Phi)/dt. Answer: Mutual inductance: changing primary current produces changing magnetic flux linked to the secondary. Why not the others:* DC current cannot maintain induction because magnetic flux remains constant (d(Phi)/dt = 0).
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