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:

Using Rydberg's formula $\frac{1}{\lambda} = R \left(\frac{1}{n_1^2} - \frac{1}{n_2^2}\right)$, we substitute $n_1=2$ and $n_2=4$. $\frac{1}{\lambda} = R \left(\frac{1}{4} - \frac{1}{16}\right) = \frac{3R}{16}$. This gives $\lambda = \frac{16}{3R}$.