When the wave of hydrogen atom comes from infinity into the first orbit then the value of wave number is

109700 cm–1 1097 cm–1 109 cm–1 None of these

109700 cm–1

Wave number $\bar{v}=\frac{1}{\lambda}=R\left[\frac{1}{n_1^2}-\frac{1}{n_2^2}\right] ; n_2=\infty$ and $n_1=1$ $\Rightarrow \bar{v}=R=1.097 \times 10^7 ~m^{-1}=109700 ~cm^{-1}$