## In This post you will get answer of Q.

The largest wavelength in the ultraviolet region of the hydrogen spectrum is $122 ,nm$. The smallest wavelength in the infrared region of the hydrogen spectrum (to the nearest integer) is

Solution:

## The series in U-V region is Lymen series. Longest wavelength corresponds to minimum energy which occurs in transition from n = 2 to n = 1. …(i)

The smallest wavelength in the infrared region corresponds to maximum energy of Paschen series.

$therefore lambda= frac{1}{R}$…(ii)

Solving Eqs. (i) and (ii), we get

$lambda=823.5 nm$