Question

select the true statements about sound waves.
choose 2 answers:
a sound waves need a matter medium to travel through.
b all sound waves have the same amplitude and
frequency.
c sound waves travel at different speeds in different
mediums.
d human ears can hear all sound waves directly.

Explanation:

• Option A: Sound waves are mechanical waves, so they require a medium (solid, liquid, gas) to travel. This is correct.
• Option B: Sound waves can have different amplitudes (affecting loudness) and frequencies (affecting pitch), so this is incorrect.
• Option C: The speed of sound depends on the medium (e.g., faster in solids than in gases), so sound waves travel at different speeds in different mediums. This is correct.
• Option D: Human ears can only hear a limited range of sound waves (audible range), not all (e.g., ultrasonic or infrasonic waves can't be heard directly), so this is incorrect.

Answer:

A. Sound waves need a matter medium to travel through.
C. Sound waves travel at different speeds in different mediums.