Question 23M.1.SL.TZ1.17

A standing wave with a first harmonic of frequency $f_1$ is formed on a string fixed at both ends.

The frequency of the third harmonic is $f_3$.

What is $\frac{f_1}{f_3}$?

A.  3

B.  $\frac{3}{2}$

C.  $\frac{2}{3}$

D.  $\frac{1}{3}$