Question

what characteristic of sound would change if there is a change in its ampliyude

Answer 1

The change in the amplitude of a sound wave results in the change in the loudness of the sound wave .
Higher the amplitude louder is the sound and lower the amplitude feeble is the sound.

Answer 2

If there is a cgange in amplitude there is a change in loudness....
As with increase in loudness there is an increase in amplitude.