How does the standard cell potential tell you about whether 1) a species is oxidizing or reducing? 2) how strong of an oxidizing or reducing agent the species might be?

The standard cell potential helps to determine the oxidative and reductive strength of species. All the species that lie below the Standard Hydrogen Electrode in the standard cell potential table are stong oxidizing agents and are highly electronegative while those that are above the Standard Hydrogen Electrode are either weak oxidants or reducing agents

speed of light in vacuum is 300,000 km/s

speed of light in other mediums is given by the expression v = c/n, where c is the speed of light in vacuum and n is the refractive index of medium.

for the first medium v = 200,000 km/s

  so, refractive index of medium = 300000/200000 = 1.5

    1.5 refractive index is usually for glass. so first medium is glass.

for the second medium v = 250,00 km/s

so, refractive index of medium = 300000/250000 = 1.2

    1.2 refractive index is usually for water. so second medium is water.

for the third medium v = 0 km/s

so, refractive index of medium = 300000/0 = ∞

    ∞ refractive index is usually for opaque mediums. so third medium is opaque medium.