Atomic Structure: Practice Problem & Solution

Solution Explained:

To solve this problem, we apply the core principles of Atomic Structure. Understanding the underlying formula is key to arriving at the correct answer below:

The number of possible spectral lines emitted when transitioning from the nth state to the ground state is $\frac{n(n-1)}{2}$. For $n=4$, the number of lines is $\frac{4 \times 3}{2} = 6$.