What describes the arrangement of two coils of wire in proximity to facilitate induction?

The arrangement of two coils of wire positioned near each other to facilitate electromagnetic induction is best described as an air core transformer. In this setup, one coil, often referred to as the primary coil, generates a magnetic field when an alternating current passes through it. This magnetic field can then induce a voltage in the second coil, known as the secondary coil, through the principle of electromagnetic induction.

The term "air core" specifically indicates that there is no ferromagnetic material, like iron, within the coils to enhance the magnetic coupling. Air core transformers are effective for certain applications, especially where lightweight or specific frequency performance is required. The absence of a core material influences the efficiency and strength of the induced voltage depending on the distance between the coils and the number of turns in each coil.

Other options like an iron core transformer utilize a magnetic core to increase coupling and efficiency, whereas inductors and capacitors are components that work through different electrical principles. Inductors store energy in a magnetic field created by the current flowing through the wire, while capacitors store energy in an electric field. Thus, the defining feature of two coils arranged for induction is best captured by the air core transformer description.