(a) Show that the various lines in the hydrogen spectrum can be expressed in angstroms as
$$
\lambda(\dot{A})=\frac{911 \mathbf{n}_{1}^{2} \mathbf{n}^{2}}{\mathbf{n}^{2}-\mathbf{n}_{1}^{2}}
$$
where $\mathbf{n}_{1}=1$ for the Lyman series, 2 for the Balmer series, and 3 for the Paschen series. The integer $\mathbf{n}$ is larger than $\mathbf{n}_{1}$.
(b) Calculate $\lambda$ for the Lyman series to $\mathbf{n}=5$, the Balmer series to $\mathbf{n}=7$, and the Paschen series to $\mathbf{n}=10 .$ Plot the results as in Fig. $2-2 .$ What are the wavelength limits for each of the three series?