Answer: The correct answer is "medium".
Step-by-step explanation:
The expression for the relation between the speed of the wave and frequency is as follows;
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Here, v is the speed of the wave, f is the frequency of the wave and
is the wavelength of the wave.
There is an inverse relationship between the frequency and wavelength. If the frequency of the wave increases then the wavelength of the wave decreases while the speed of the wave remains constant.
The properties of the wave can be described by amplitude, wavelength and frequency but the speed of the wave depends on the medium through which it is moving. The medium may be denser or rarer according to it the speed of the wave will vary.
Therefore, in the waves lab, you changed medium to see how it would affect wave speed.