\(\therefore\) \(\,\frac{1}{{{\lambda _{\max }}}}\,\, = \,\,R\,\,\left[ {\frac{1}{{{4^2}}} - \frac{1}{{{5^2}}}} \right]\,\,\,\,\,\)
\(\Rightarrow\) \({\lambda _{\max }}\) \( = \,\,\frac{{25\,\, \times \,\,16\,\, \times \,\,{{10}^{10}}}}{{9\,\, \times \,\,1.1\,\, \times \,\,{{10}^7}}}\)
\(=\,\,40400\, Å\)