An imperfect authentic cadence is defined as what?

• A. V to I with the I in root position.
• B. V to I with the I not in root position.
• C. V to I where the I is in a non-root position or tonic in the upper voice; not both chords in root position.
• D. I to V.

Answer: (C)

An imperfect authentic cadence keeps the V to I target, but it lacks the strong final pull of a perfect cadence. A perfect authentic cadence needs both chords in root position and the final I chord to present the tonic in the soprano. If the I chord isn’t in root position, or the tonic is in the upper voice on the final chord, the closure isn’t as definitive. So the best description is a V to I where the I is in a non-root position or the tonic appears in the upper voice, with not both chords in root position. This captures the common ways the cadence loses its perfection while still moving to the tonic.