How do you differentiate plagal cadences from perfect cadences?

Hi, I'm currently about to take ABRSM grade 8 practical exam for piano in a few months' time. Part of the aural section require candidates to recognise and name the different cadences after listening to a piece played by the examiner. I always have problems differentiating the plagal and perfect cadences. I know that one is IV-I and the other V-I but this is not useful to me as I must recognise them by listening only, I can't look at the notes. So, hopefully some of you can tell me how it sounds differently and give me some advice! thanks (:

Listening for the tonic helps me a lot.

The plagal cadence contains the tonic (DO) in both chords, but the perfect cadence has the leading tone (TI) in the first chord and the tonic (DO) in the second.

Example:
Plagal - fa la DO ---- DO mi so
Perfect - sol TI re ---- DO mi so

(in minor...)
Plagal - fa le DO ---- DO me so
Perfect - sol TI do ---- DO me so


In simpler terms, the V chord in the perfect cadence leads to the I chord, but the IV chord in a plagal cadence sounds more like a suspension.

Good luck on your test!

The plagal cadence is also known as the "Amen" cadence (as many hymns which end with "Amen" harmonize it with a plagal cadence.)

So if you hear a cadence and can imagine singing "Amen" to it, it's a plagal cadence.

As the other responder suggested, the plagal cadence is usually used in hymns, especially on the "Amen."

If you can hear the root notes of the chords, try counting the number of steps between the interval formed at the cadence. Beginning on the higher note, think:

Sol - (Fa - Mi - Re) - Do ... which would suggest a perfect cadence, or
Fa - (Mi - Re) - Do ... which would suggest the plagal cadence.

In the plagal cadence (IV - I ) the tonic of the scale is the shared note. In the key of C (for example) there is a C that is common to both of the chords, and in most plagal cadences they will emphasize this note not moving.

A perfect cadence (V - I or vii dim - !) there are no shared notes, so all of the notes are moving.

Whoa, the other posters gave realy good answers but im just curious - how in the world did you survive grade 7 and 6 then? By guessing? By the time you're in grade 8 you supposed be able to recognise them already.

Thinking "amen" is the best way to hear a Plagal cadence. For perfect cadences you can just think of every boring pop song on the radio.