Question

Calculate the total number of possible spectral lines in the UV region, during the transition of an electron from the $4^{\text{th}}$ excited state to the ground state in a sample of Hydrogen atoms.

• A. $5$
• B. $10$
• C. $4$
• D. $2$

Answer 1

The correct option is C $4$

Maximum number of spectral lines$\left(N\right)$ corresponding to transition from $n_1=5$ to $n_2=1$ are:
$N=$ number of lines emitted $=\frac{1}{2}(n_1-n_2)(n_1-n_2+1)$
$=\frac{1}{2}(5-1)(6-1+1)$
$=10$
Here the transitions in lyman series fall under UV spectrum.
Therefore, transitions under UV spectrum are four $(5\to 1,4\to 1,3\to 1\text{and}2\to 1)$