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The wavelength of the radiation emitted, when in hydrogen atom electron falls from infinity to stationary state $$1$$, would be (Rydberg constant $$= 1.097 \times 10^7$$ m$$^{-1}$$)
The electron is falling from $$n_2=\infty$$ to the first stationary state $$n_1=1$$ in a hydrogen atom. Such transitions belong to the Lyman series.
Using the Rydberg formula,
$$\frac{1}{\lambda}=R_HZ^2\left(\frac{1}{n_1^2}-\frac{1}{n_2^2}\right)$$
For hydrogen, $$Z=1$$, $$n_1=1$$ and $$n_2=\infty$$.
Substituting these values,
$$\frac{1}{\lambda}=1.097\times10^7\left(\frac{1}{1^2}-\frac{1}{\infty^2}\right)$$
Since,
$$\frac{1}{\infty^2}=0$$
the equation becomes
$$\frac{1}{\lambda}=1.097\times10^7\ \text{m}^{-1}$$
Therefore,
$$\lambda=\frac{1}{1.097\times10^7}\ \text{m}$$
$$\lambda=0.9115\times10^{-7}\ \text{m}$$
Converting into nanometers,
$$\lambda=0.9115\times10^{-7}\times10^9\ \text{nm}$$
$$\lambda=91.15\ \text{nm}$$
Hence, the wavelength of the emitted radiation is
$$\boxed{91\ \text{nm}}$$
Thus, the correct answer is Option (A).
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