What cadence is formed when IV is followed by I?

The cadence formed when the IV chord is followed by the I chord is known as a Plagal Cadence. This particular cadence is characterized by the resolution from the subdominant (IV) to the tonic (I), creating a sense of finality and rest, often described as the "Amen" cadence due to its frequent use in hymns and religious music.

This progression emphasizes the relationship between the IV and I chords, contributing to a smooth and satisfying conclusion to a musical phrase. The concept of tonal resolution is central to understanding cadences in music theory, and the Plagal Cadence specifically highlights the tonic's stability after moving from the IV chord.

While other cadences, such as Authentic, Half, or Deceptive, involve different progressions and resolutions, the specific movement from IV to I distinctly identifies the Plagal Cadence, making it the correct choice in this context.