Answer:
1) 341 Hz
Explanation:
When a string vibrates, it can vibrate with different frequencies, corresponding to different modes of oscillations.
The fundamental frequency is the lowest possible frequency at which the string can vibrate: this occurs when the string oscillate in one segment only.
If the string oscillates in n segments, we say that it is the n-th mode of vibration, or n-th harmonic.
The frequency of the n-th harmonic is given by
where
n is the number of the harmonic
is the fundamental frequency
Here we have:
is the frequency of the 3rd harmonic
So the fundamental frequency is
And so, the frequency of the 2nd harmonic is: