Question

Which wave property determine (a) loudness , (b) pitch?​

Answer 1

Loudness is determined by 'amplitude'.

Pitch is determined by 'frequency'.

Answer 2

$\small\mathcal\pink{(a)\: Amplitude:-}$ The loudness of the sound and its amplitude is directly related to each other. Larger the amplitude louder is the sound.

$\small\mathcal\pink{(b)\: Frequency:-}$ The pitch of the sound and its frequency is directly related to each other. If the pitch is high then the frequency of sound is also high.