Final answer:
The property of waves that remains constant in an oscillator creating periodic waves on two strings is frequency.
Step-by-step explanation:
The property of waves that remains constant in an oscillator creating periodic waves on two strings is frequency. Frequency is the number of oscillations or cycles that occur in a given time period. It is measured in hertz (Hz) and represents how fast the waves are repeating themselves.
In an oscillator, the amplitude, wavelength, and velocity of the waves may vary, but the frequency remains constant. The amplitude refers to the maximum displacement or height of the wave, the wavelength is the distance between two corresponding points in the wave, and the velocity is the speed at which the wave is traveling.