a sounds wave forms a thir harmonic stanidng waves un a resonant cavity with the length of $2\mathrm{.}5$m a$)$ how many nodes are there in this standing wave? b$)$ what is the longest wavelenth stanfing wave could be formed in such a cavity c$)$ for this fundamental harmonic standing wave $,$ calculate the distance it can travel $100$ periods. d$)$ If the speed of the sound is $343$ m$/$s$,$ calculate the frequency of the wave