Sonometer Experiment: Measuring AC Mains Frequency

[Ali Asadullah]

We did an experiment of measuring AC mains frequency using sonometer. In the experiment an electromagnet was vibrating the string. We adjusted the length of the string so that the amplitude is maximum. My question is that resonance was there in vibration or not. How the amplitude was changing with the change in length of the string

 

[graphene]

A stretched sting has certain vibrational modes (frequencies) only.
This depends upon the length of the sting. It also depends upon the tension in the string & the string's material.

When you matched the natural frequency of the string (by changing the length) with the external frequency, it started to resonate.