Correct Option: B

A transformer is a power converter that transfers electrical energy from one circuit to another through inductively coupled conductors—the transformer’s coils. A varying current in the primary winding creates a varying magnetic flux in the transformer’s core and thus a varying magnetic field through the secondary winding. This varying magnetic field induces a varying electromotive force (EMF), or “voltage”, in the secondary winding. This effect is called inductive coupling. The transformer is based on principle of mutual induction in which, firstly, that an electric current can produce a magnetic field (electromagnetism) and second that a changing magnetic field within a coil of wire induces a voltage across the ends of the coil (electromagnetic induction). Changing the current in the primary coil changes the magnetic flux that is developed. The changing magnetic flux induces a voltage in the secondary coil.