Answer
Please see the work below.
Work Step by Step
(a) We know that there is no upper limit for wavelength $\lambda$.
(b) We can find the lower limit as follows:
$\frac{1}{\lambda}=R(\frac{1}{(1)^2}-\frac{1}{\infty^2})$
$\implies \lambda=\frac{1}{R}$
$\lambda=\frac{1}{1.097\times 10^7}$
$\lambda=91.2nm$