The diagram shows a transformer. [Figure 36.1] A student writes four statements about how the transformer works. 1 An alternating voltage across the primary coil induces an unchanging voltage across the secondary coil. 2 An alternating voltage across the primary coil produces a changing magnetic field in the iron core. 3 A changing magnetic field in the iron core induces an alternating voltage across the secondary coil. 4 An unchanging voltage across the primary coil produces a changing magnetic field across the secondary coil. Which statements explain how the transformer works?

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