The wavelength of the radiation emitted, when in a hydrogen atom electron falls from infinity to stationary state 1, would be ( Rydberg constant $$ = 1.097 \times {10^7}{m^{ - 1}}$$    )

Solution :
TIPS/Formulae :
$$\eqalign{ & \frac{1}{\lambda } = R\left( {\frac{1}{{n_1^2}} - \frac{1}{{n_2^2}}} \right) \cr & \frac{1}{\lambda } = 1.097 \times {10^7}\left( {\frac{1}{1} - \frac{1}{\infty }} \right) = 1.097 \times {10^7} \cr & \lambda = 91.15 \times {10^{ - 9}}m\,\, \approx \,\,91nm \cr} $$