Physics - Error Question with Solution | TestHub

A tunning fork of frequency$480 \mathrm{H}\mathrm{z}$is used in an experiment for measuring speed of sound$\left(v\right)$in air by resonance tube method. Resonance is observed to occur at two successive lengths of the air column,$l_1=30\mathrm{c}\mathrm{m}$and$l_2=70\mathrm{c}\mathrm{m}.$Then,$\nu$is equal to: