Answer: 9.675 Hz .
Explanation:
Given, velocity of waves = 12.9 m/s
Length of string = 2.00 m
Let [tex]\lambda[/tex] be the wavelength , then for 3 loops
[tex]\dfrac{3}{2}\lambda= \text{length of string}\\\\\Rightarrow\ \dfrac{3}{2}\lambda= 2\ m\\\\\Rightarrow\ \lambda= \dfrac{4}{3}\ m[/tex]
Now , velocity = frequency x wavelength
Then, frequency = [tex]\dfrac{velocity}{wavelength}[/tex]
[tex]=\dfrac{12.9\times3}{4}\\\\=9.675\ Hz[/tex]
hence, it will create standing waves with 3 loops at 9.675 Hz .
