Question

As an ambulance siren passes and moves away from you, the sound waves'

frequency __________
and their amplitude ________

A. increases,
decreases
B. increases,
increases
C. decreases,
increases
D. decreases,
decreases

Answer 1

`\qquad\qquad\huge\underline{{\sf Answer}}♨`

Amplitude and frequency are two properties of sound waves that decreases as distance from source decrease.

Therefore, as the ambulance moves away,

• frequency - decreases
• amplitude - decreases

So, correct choice is D