The electron in hydrogen atom is initially in the second excited state. When it finally moves to ground state, the maximum number of spectral lines emitted are

The ground state of a hydrogen atom corresponds to the principal quantum number $n = 1$.

The second excited state corresponds to $n = 3$.

The maximum number of spectral lines emitted when electrons transition from an excited state $n$ to the ground state is given by the formula:

Number of spectral lines = $\dfrac{n(n-1)}{2}$

Substituting $n = 3$ into the formula:

Number of spectral lines = $\dfrac{3(3-1)}{2} = 3$

The $3$ possible transitions are:
$n = 3 \rightarrow n = 1$
$n = 3 \rightarrow n = 2$
$n = 2 \rightarrow n = 1$

Answer: $3$