Question

Calculate the total number of spectral lines in the UV region, during the transition from the $5^{th}$ excited state to the $1^{st}$ excited state in a sample of Hydrogen atoms.

• A. 10
• B. 3
• C. 4
• D. \N

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 $=\frac{1}{2}(n_1-n_2)(n_1-n_2+1)$
$=\frac{1}{2}(5-1)(5-1+1)$
$=10$
All transitions in lyman series fall under UV spectrum.
Therefore, transitions under UV spectrum are $four(5\to 1,4\to 1,3\to 1and2\to 1)$
Number of possible transitions $=4$