does a hollow prism split white light into its constituent colours?
Answer Sure, just not very much. Passing light through a hollow prism is effectively the same as passing light through two plate glass sheets. For light passing through a plate glass sheet, the incoming and outgoing angles are equal and opposite for all wavelengths. Therefore, the dispersion (spread into colors) incurred by refraction on the incoming and outgoing surfaces cancels. There is a small residual dispersion because of the spread of wavelengths inside the plate glass. The glass would have to be quite thick for this to be noticed.
