Answer
$\lambda^{\prime}=388nm$
Work Step by Step
We know that
$\lambda^{\prime}=\frac{\lambda}{n}$
We plug in the known values in the formula to obtain:
$\lambda^{\prime}=\frac{589\times 10^{-9}}{1.52}$
$\lambda^{\prime}=388\times 10^{-9}$
$\lambda^{\prime}=388nm$
