Question

In an electronic transition from n = 1 to n = 5 in hydrogen atom, the spectrum contains __________ number of lines.

• A. 5
• B. 8
• C. 10
• D. 12

Answer 1

The correct option is C 10

When an electron jumps from $n_2=5\text{to}{n}_1=1$ the following transitions are possible.
$5\to 4$
$5\to 3$
$5\to 2$
$5\to 1$
$4\to 3$
$4\to 2$
$4\to 1$
$3\to 2$
$3\to 1$
$2\to 1$
Hence there are 10 transition which are possible.