why energy can be transferred between two coils with similar resonant frequencies

Energy can be transferred between two coils with similar resonant frequencies because of the phenomenon of resonance. When two objects have the same resonant frequency, they are able to transfer energy back and forth between each other with maximum efficiency. In the case of two coils with similar resonant frequencies, when one coil is excited with an alternating current, it creates a magnetic field that induces a voltage in the second coil. This voltage can be used to power a device or charge a battery. The transfer of energy is most efficient when the two coils are in close proximity and have the same resonant frequency.