Which of the following are the result of developments in science ?

Hello!

Your answer is all of the above. Science is a very broad field, and it is the thing which has engineered most, if not all, of our technology today. Take for example microwave ovens. These could not have been possible without science, as it was science that realized that "microwaves" (a type of wave length) even existed.

Hope this helps!

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.

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