Physics - Sound Wave Question with Solution | TestHub

Each tuning forck gives 3 beats with the next, so the difference in the frequencies of two consecutive forks is 3 . $\begin{array}{rl}\therefore f_{26}& =f_1+(n-1)\times -3\\ f& =2f+(26-1)\times -3\\ f& =75\mathrm{Hz}.\end{array}$ $\therefore$ Frequency of 18 th tuning fork $\begin{array}{rl}{f}_{18}& =f_1+(18-1)\times -3\\ & =2\times 75+17\times -3\\ & =150-51=99\mathrm{Hz}\end{array}$