Answer:
D. Frequency
Step-by-step explanation:
The machine produces compression waves in a spring that is 120cm long and it pulse twice every seconds. The property the wave exhibits by exhibiting the value of two per second is the Frequency.
Amplitude of a a wave is the maximum displacement from the equilibrium position. The amplitude of an object is equal to one half the path of the vibration path. The amplitude of a wave is proportional to the amplitude of the source. Amplitude measures how big a wave is . Amplitude of a wave usually look at the energy of a wave so it is not the amplitude .
The frequency of a wave gives the number of wave that passed fixed point at a given time.