Frequency of sonometer wire \(n \propto \frac{1}{l}\).
\(\therefore \) \(\frac{{n + 4}}{{n - 4}} = \frac{{100}}{{95}}\) or \(95\,(n + 4) = 100(n - 4)\)
or \(95n + 380 = 100n - 400\) or \(5n = 780\) or \(n = 156\)
(હવામાં ધ્વનિની ઝડપ $=330\, ms^{-1}$)