Determine how many wavelengths will fit into the glass container when it is a vacuum. Since the light passes through the container twice, you need to determine how many wavelengths will fit into a glass container that has a length of 2L.

   # = 2L /λ

Explanation:

For this exercise we can use a direct proportion rule. If there is 1 wave in 1 wavelength in 2L wave how many lengths are there

                    # = 2L /λ 1 wave

let's calculate

                  # = 2L /λ

we see that the longer the wavelength the fewer waves fit in the container

in order to follow the instructions and complete the statements, i need to use data from table c of your student guide. can you think of a way to let me see your student guide for a while ? i can't answer the question without the data in table c.