How do
astronomers use light to
learn about our Universe?

because if the tool that you are using is not balanced it there would be false mass.

snell's law

refractve index = sin incidence / sin refraction

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.