Question

When the electron of a hydrogen atom jumps from $n=4$ to $n=1$ state, the number of spectral lines emitted is

• A. 15
• B. 9
• C. 6
• D. 3

Answer 1

Answer: (C)

When an electron jumps from $n$ to ground state (ie, $n=1$ ),
the number of spectral lines $=\frac{n(n-1)}{2}$
$\therefore$ When an electron jumps from $n=4$ level number of spectral lines $=\frac{4(4-1)}{2}$
$=\frac{4\times 3}{2}=6$