What must be present for electromagnetic induction to occur inside a transformer?

For electromagnetic induction to occur inside a transformer, all the listed factors must be present. The process relies on the interaction between electrical and magnetic fields, fundamentally governed by Faraday's law of electromagnetic induction.

A magnetic field is crucial, as it is created by the alternating current in the primary coil of the transformer. This changing magnetic field induces an electromotive force (EMF) in the secondary coil, facilitating energy transfer.

A continuous voltage source is necessary to provide the electrical energy that will create the magnetic field. Without a voltage supply, there would be no current flow in the primary coil, and consequently, no magnetic field would be generated.

Additionally, conductors, such as the coils themselves, are required to allow the flow of electric current. The primary and secondary coils act as the conductors through which the electrical current flows and where the induction takes place.

In summary, the presence of a continuous voltage source ensures that current flows, the magnetic field enables the process of induction, and conductors carry the current—all of which are integral for the transformer to function effectively.