Question

If Paschen series of hydrogen spectrum has $4$ lines then number of lines in Balmer series will be:

• A. $3$
• B. $5$
• C. $6$
• D. $2$

Answer 1

The correct option is B $5$

Paschen series of hydrogen spectrum has 4 lines
Paschen series corresponds to transitions upto $n=3$
Four lines corresponds to transitions $7\to 3$, $6\to 3$, $5\to 3$ and $4\to 3$
Balmer series corresponds to transitions upto $n=2$
It will have transitions $7\to 2$, $6\to 2$, $5\to 2$, $4\to 2$ and $3\to 2$
The number of lines in Balmer series will be 5.