\(\frac{1}{\lambda_0}=R\left(\frac{1}{2^2}-\frac{1}{3^2}\right)\)
\(\frac{1}{\lambda_0}=R \frac{5}{36}\)
\(\frac{1}{\lambda_1}=R\left(\frac{1}{2^2}-\frac{1}{4^2}\right)\)
\(\frac{1}{\lambda_1}=R\left(\frac{1}{4}-\frac{1}{16}\right)\)
\(\frac{1}{\lambda_1}=R \frac{3}{16}\)
\(\frac{\lambda_1}{\lambda_0}=\frac{5}{36} \times \frac{16}{3}\)
\(\lambda_1=\frac{20}{27} \lambda_0\)