Question

When would the velocity of a wave traveling in a medium change?
A. only if a property of the wave changes
B. only if a property of the medium changes
C. if a property of both the wave and the medium changes
D. never

Answer 1

From a random website:

"The main properties of waves are defined below.
Amplitude: the height of the wave, measured in meters.
Wavelength: the distance between adjacent crests, measured in meters.
Period: the time it takes for one complete wave to pass a given point, measured in seconds.
Frequency: the number of complete waves that pass a point in one second, measured in inverse seconds, or Hertz (Hz).
Speed: the horizontal speed of a point on a wave as it propagates, measured in meters / second."

which makes me think there is something somewhat circular or chicken/egg about this question....