Answer:
Frequency and period
Explanation:
When the guitar vibrates, it sets the air molecules also into vibration and these waves will exhibit same frequency. Since period of a wave is reciprocal of frequency and in this case the frequency is the same then the period will also be similar. The speed of waves will be different since the waves will have different wavelengths and speed is product of wavelength and frequency. Therefore, both the period and frequency are the same.