## Physics for Scientists and Engineers: A Strategic Approach with Modern Physics (4th Edition)

The index of refraction of the walls is $~~1.52$
We can use this formula: $d = (\frac{n_2}{n_1})~d'$ where $d$ is the actual distance and $d'$ is the apparent distance. We can find the index of refraction of the walls $n_2$: $d = (\frac{n_2}{n_1})~d'$ $n_2 = \frac{n_1~d}{d'}$ $n_2 = \frac{(1.33)(4.00~mm)}{3.50~mm}$ $n_2 = 1.52$ The index of refraction of the walls is $~~1.52$