Thank you for reporting, we will resolve it shortly
Q.
When the electron of a hydrogen atom jumps from $n = 4$ to $n = 1$ state, the number of spectral lines emitted is
AMUAMU 2010Structure of Atom
Solution:
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 $=\frac{4(4-1)}{2}$
$=\frac{4 \times 3}{2}=6$